Thank you for such an informative video! I’ve been telling guys since the early 80’s that you have to spec your components for what you want out of it. They always said bigger is always bigger and you have to chrome it, etc. I’ve grown up trucking in my blood with the family business. Every truck is different and has to be spec’s out for different applications. If you spec it wrong, it will not be able to do what it was intended for and you can’t make money from it. It will end up costing you more money just to operate if at all. You explained it very well. You have to first figure out what you want out of it and go from there. That is why so many guys go and buy that dream car and end up crashing it moments after picking it up. You have to know what the vehicle is capable of doing and what you are capable of doing also. Once you get all the parts of the equation down, you will have a near perfect machine! I say near perfect because we are never satisfied once you start down this road. lol! Thanks!
Thank you! You bring up lots of good points. I like to take as much guess work out of things. If you can at least have a process, you can anticipate the results.
Even before seeing this, I believe most guys have too much carburetor on their engine. 750 cfm seems to be the default carb everyone uses, but I chose a 600 cfm for my bone stock 396 325 hp big block. The street manners and throttle response are impressive, better than any of my injected engines in fact. I've had many guys tell me I need a 750, that a 600 is too small etc. but nope.
Really all depends on what you use it for and what it’s set up for. I worked on a set up this morning that was WAY over carburated. I offered to tune one of mine on his set up to prove it. It really common and like you mentioned, doing it right will get you a better running engine. Thanks for watching!
Interesting, anybody's 350 cid V8 at 5000 rpms only needs around 375 cfm, maybe 400 cfm at 5000 rpms, and most street cars never go to a higher rpm than this. Yet most guys never go lower than 650 on a carb, and many go to 750. We need to be realistic when we enter data as to what the revs are going to top out at.
True. It’s easier to pick one carburetor and put it on everything than to switch it up. Doesn’t mean the engine is using all 750 cfm. They put 750’s on 305’s and the secondaries wouldn’t even open all the way even at 5500 rpm.
Nice! That’s pretty cool actually. 😆 I’ve always wanted to be background noise! Thanks for the laugh. I really do appreciate that and glad you found a way to listen. It’s a great idea! I might start doing the same.
Few weeks ago Brian helped me work through picking the proper fuel delivery for a project I'm working on; very nice and knowledgeable guy. Thanks again Brian.
I just had an "Ah-ha!" moment at @16:10 . It took me a couple runs through your other good videos. U never know what you missed when you don't understand stuff. Thank you, again!
When towing or using engine in a heavy vehicle go smaller CFM. Air Velocity is what we are after in carburetor sizing. We want high air velocity so the carburetor works properly plus to fill the cylinders well especially at low rpms. If air velocity falls off due to carburetor being to big low end suffers. That's why smaller for towing and heavy vehicles. You can go bigger with lighter vehicles and higher rpms engines. When driving on the street we don't see much past 3500 rpms so the high air velocity of a smaller carburetor provides a much better driving experience. Good stuff!
I had a '77 Camaro back in the mid to late 80's that had a .40 over 350 with flat top pistons, roller rockers, stock exhaust manifolds a TH-350 trans, stock converter with 3:08 rear gears and 305 two barrel heads with small ports and an RV type camshaft ( I don't remember the brand name or specs on it though) that had an almost stock idle but you could tell it wasn't completely stock, the intake was a dual plane Edelbrock performer and I put on a 600 Holley with vacuum secondaries. I dont remember if the Edelbrock carburetors were around yet but the Holley was just over $100 brand new back then. I never had to fool with the jets or anything other than the idle speed and mixture, it ran pretty well out of the box. I ended up daily driving that car for quite some time. I had to watch the fuel quality and timing since the 305 heads bumped up the compression a bit but it had excellent throttle response and averaged around 17 MPG on the highway. I'm sure the cam, heads and exhaust held back any real top end performance but the low end torque was good enough for what I used the car for since it rarely saw anything over 4-5K RPM. I still regret selling it along with the other old cars I used to have which were cheap and plentiful back then.
Thank you for the great video. I am trying to find the best carb for my 77 CJ7. It has the IL 258 with a mild low torque cam (I don't know the specs), Offenhauser four barrel intake, electronic ignition and headers. This Jeep gets limited use, but is used both off-road and street. Definitely not high rpm street racing obviously. Carb must be able to handle off road hill climbing without cutting out. I am leaning towards possibly a two barrel 350-400cfm carb with an adapter to the 4 barrel manifold. Any suggestions? Thank you
@@bryangalvin4205 off road applications can get tricky. You know what situations you’ll be putting this into. I would agree the smaller CFM carb would be your best bet. Depending on the HP level, you might also consider a TBI efi set up. That would be your best bet depending how extreme your off road adventures are.
Just ran across this video. It was VERY informative. Here is my dilemma: I have a stock 350 sbc in a 72 Impala coupe (weighs about 3900 lbs.) with a 200R4 transmission and 3.73 rear end. An Edelbrock 1406 (600 cfm) sits atop a dual plane intake manifold that is fed by in-tank pump (max psi: 49-50) regulated to 5.5 psi by an AER fuel regulator. Max RPM for the engine is 5500; however, I have yet to hit 4000 even on the hills in my locale (3800 was the highest so far). I do not race but use the 3.73 gears for acceleration and the 200's OD to cruise. The 1406, IMO, burns too much gas. Edelbrock recommends the 1406; however, an older mechanic I know suggested moving to the 1404 (500 cfm). The math in your video also supports that mechanic. I'm looking for a final confirmation prior to spending the money for a new carb.
If you’re only spinning it to 4000 rpm, then that’s your number. Make the switch to a 500 and then TUNE it for your application. It’s not correct right out of the box. Never is. Once it’s tuned, then you can determine if it was the right move. Sounds like it will be.
If anybody is wondering the 3456 comes from converting cubic inches to cubic feet and from considering that the car is 4 stroke meaning you will only pull air every other rotation.
Man iv follow you. I got a 350. 1972 Monte. It's a cruiser. But she likes to go fast. I put the fuel just like you I'm sitting at 5000 in Colorado. Adjustments made according to the chart. Still runs rich rich
thanks for clearing alot of this up, I have been looking for a Holley DP for my 466 BBF in my 78 f100 street/strip truck (mostly street realistically), have been concerned about going to little or wasting time over carbureting
I'm running a junkyard low compression dodge 360 , edelbrock 340 manifold , A body manifolds true dual in a 3300 lb car and 373 diff with a edelbrock 600 cfm , mostly in town driving . Runs great , amazing fuel mileage and spark plugs are a light brown .
Lol, here I am again listening to your videos. Just put all the side markers in my Mach 1. A tie rod end. And adjusted my reverse band all while listening to these
My car has the hated 301 and is factory turbocharged with an 850 cfm carburetor from the factory and it works great, it is a small turbo not a high horsepower engine it doesn’t run rich and it has a perv valve I believe is called that helps with the fuel mixture. Great video. Carburetors are a mystery.
First - Thanks so much for all your Wonderful Video's. I've never been very well versed in Cars/Working on them. But have just acquired a new care "to me" and have been trying to learn about Carbs and how they work and how to work on them and your video make thing very clear and understandable even for a 71 yr old Rookie ;-) So, I have a 1990 Chevy 383 Stroker Motor, in a lightweight car (2700lbs) not sure of any of the internals with the exception Of it came with documents for an Isky Mega 280 Cam, and it has an Edelbrock 1405 that has had an Electric Choke added at some point. I did check the Metering Rods and they are the .070 x.047. I've been learning about the timing and have 18 deg Adv and 34 in at about 2500rpm. Hope this is enough information to be able to make some suggestions. Thanks again, Take Care, CK
Glad you’re enjoying the videos! So the root question here is the 600 the right carb for the 383 in a light car. First things first. We have to ask the question, “what are you doing with the car”? Just a fun cruiser or something more aggressive? I don’t know a thing about the specs on that cam but I’ll assume they’re around 230 and a fairly tight LSA. 107? That cam is likely going to be done by 6500, so now we know what the max rpm is. The rest is simple from the video. On a lighter car, a little more CFM isn’t a bad thing. If you’re going to work in the power band of that cam (if my assumptions were correct) then a 750 would be a great carb for that set up. Just have to make sure the rest of the engine combination match and you’ll have a screamer of an engine!
Hi, Thanks so much for the reply and information. I'm just going to be cruising around in it on Nice Sunny Days. I think all in at 6500 is probably all my Heart can take ;-) Appreciate everything, Take Care, CK
@@CKirk2727 I just found that cam. It’s not going to be a lot of fun for a cruiser. It will sound good, but it’s going to be down on power below 2500. Not very fun. I’m assuming that’s what you’re after though. In which case, the 600 might be ok.
Hi, LOL I had that feeling even with the short amount of time I've had it and driven it. BUT It is what it is, at least now I know and so that will make things a lot clearer on it's performance, and drivability, and makes me feel a little better about my driving and tuning attempts. Thanks so much again for all your Help and the Great Video's I've learned a lot !!!
Hi there so I have a 78 bronco with a 460 out of a 70s motorhome. Can’t get it to run fast and efficient lol what carb do you recommend. Currently has a 750 with Edelbrock dual plane manifold
Not sure I understand what you mean by fast and efficient. What is it doing that you don’t like and how have you attempted to tune it? What size did you come up with after watching the video?
Q-jets use the airdoor to tune the cfm.Everyone of them has at least the 750cfm potential i.e. of some rare buicktypes. The factory used the angle of the airdoor for setting the carbs to tamer or smaller engines
Correct but my understanding and experience with them since I was a young man..2 types 750 and a 800 CFM..Look down the secondary if thier is a nub sticking out.. It's a 800 CFM...looks like the tip of your pinky finger..Other wise smooth it's a 750
So glad I stumbled across this. I'm building a 351w for a 92 f150 4x4 AOD transmission. I'm running a .513 lift 270/276 duration 110 lobe separation roller cam. Stock Gt40 heads with a spring kit an edelbrock performer intake. Motor will be natural aspiration. Cam is rated 1500- 5500 rpm and intake is idle - 5500. It will be a daily driver and toy hauler. I have an edelbrock 1405 600 cfm sitting my shop now, but im wondering if I should step up to one of the new avs 650 cfm. Great content btw.
I’m glad you found it too! I don’t think you can go wrong with the AVSII. Sounds like for what you’re doing the 650 will be exactly what that combination is calling for. The windsor engines are exceptionally versatile and should deliver everything you’re asking from it!
I built a 351w 0.030 over 9.6.1 with a typhoon hi rise Intake. I also am running the same roller cam and I put it in my 87 f150 4x4 with a C6 and 3.55 gears. I have tried a 750, 725, 600 and currently using a 570 (all carbs are Holley) so far I think the 570 works the best.
Great info as usual! Appreciate all the knowledge you share with the car community, it really really helps!! Thank you and cheers from Motown. Oh, new subscriber and hit the bell.
Nice! Thanks for that. Just years and years of being around it and making many mistakes. Glad you’re here! Don’t hesitate to ask any questions. I try to answer them all. Motown thawing out and summer is almost there!
@@MuscleCarSolutions We have hit over 80 this week and set records. Scrambling to get my Mustang full spool out and go with a LSD so I can turn the darn thing. Also struggling with Deadhead or Bypass regulator. Probably Deadhead with gauge port Holley 12-840, if any problems will do bypass over winter. Mild built 460, RPM performer, Holley 4160 750,MSD 6al, C-6 manual valve body, full headers, 3" into magna flows, nodular 9" 4:11 gears, 4 link, was ex 8 sec race car, streetable now. Thanks See ya soon.
Thanks for mentioning the dump truck engine. I’m I’m the beginning stage of planning a rebuild of a Ford 460 for a stake body that it’s sole purpose is to haul firewood. Not much information about building high torque low RPM work engines.
Yup. Every year I get quite a few low rpm, high torque applications to help select components for. Dump trucks, yard dogs, logging trucks. Lots of gas powered stuff out there. Surprising how small a carb will work for a 460 when you’re only turning it less than 4000 rpm. Good stuff! Thanks for stopping by!
Love your content, I have an 86 cutlass supreme with 307, nothing else done. It would not run with the q-jet, so a friend gave me a 1406. Not looking to race, just have a little performance and decent gas mileage. I think this 1406 is way too big and getting about 10 mpg, where I used to get 20 mpg with the q-jet. Again love your channel and thank you.
i had a carter AFB 500CFM carb 20 yrs ago on my 80 impala sports coupe and that had what they called an "Rv cam" 204/214 duration @ .050 and that was more than enough had the stock freeway gears stock heads and i found a cast iron 4bbl intake
70 chevelle 10:1 383 230-240 , advertised 280-290 duration, 489 int lift, 519 exhaust, rpm air gap intake, header and full 3' exhaust, th350 2500 stall and 3:42 gears.
Great video, alot of guys over cam & over carb their street engines......I am building a 350 Vortec and I picked up a used 600cfm Edelbrock Performer(gonna do a rebuild on it just to be safe). This entire engine is being designed around that 0-5,000 rpm street tourque band. Scored a dualplane non airgap intake. If/when I change the cam I am going for a tight LSA (probobly 108) with a 0-5,000 appropriate duration etc. I am all about that throttle response since I am gonna spend waaaaay more time at 3,000 rpm vs 6,000rpm.....heck I am gonna roll manifolds since headers are a nightmare. Hp/cu-in in a light weight 2wd GMC Jimmy is gonna be FUN.
425 cadillac bored .600 due to cylinder wall damage, so 439 Cid. Stock cam. Dropped into a 64 Buick LeSaber with 3.42 rear gears. Max rpm before valve float is 4500 rpm. Torque peak is 2000, horsepower peak is 4200. I honestly thought the car had had higher rear gearing, but it was originally a manual car with a 300 Cid v8. They all got deeper rear gears. 2000 rpm is 50 mph. Top speed is 107 before valve float shuts it down. Car is primarily a weekend cruiser. I have a 750 cfm Edelbrock on it. Original carb was a 800 cfm Quadrajet.
The Qjet can be a little deceiving when you just look at the CFM number. Yes it capable of 800 CFM but I’d you look at the primaries, they are in fact substantially smaller than the secondaries. It’s how GM wanted to control the fuel and give the air and fuel needed when the demand was needed. The difference in the two carbs really can’t be compared on CFM alone. But you certainly have a lot of cubic inches to feed if you decide to go bigger on that cam! Awesome to hear you’re running a big Caddy. Always fun to see those big old school engines still on the road!
@@MuscleCarSolutions Thanks for the reply. I got the Caddy and TH400 behind it pretty cheap and went with it. It's been fun, but frustrating at times. Partly because I chose a car that isn't common, and an engine to swap that isn't common, either. I'm considering upgrading to a mild cam and stronger valve springs to go to 5000 rpm.
@@johnbutler1323 that’s the downside of the cool factor. Fewer things available for their engines that don’t have a lot of volume to support lots of aftermarket parts. Which just makes what you’re doing even cooler!
@@MuscleCarSolutions Thanks. One of the crazy things about the 425 Caddy is they debored the big 472 from 4.3" to 4.082" and kept the same 4.06" stroke. When they did, they knocked off every ounce of excess metal in the block and heads and actually opened up the water jackets quite a bit. The 425 Caddy big block weighs 100 lbs less than the 472 it's based on, putting at 525 lbs, which is 50 lbs lighter than a fully dressed Chevy small block with iron heads and intake and comes out about even when the Chevy small block has aluminum heads and intake. It's a very light engine for its displacement, especially considering it's all iron. The block is so light, I could pick it up and carry it around when it was stripped. It does take up a lot of real estate, though, and is every bit as wide as a Ford mod motor.
Putting together a 289 Ford engine in a tiny 2500 lb Sunbeam Tiger. Small 270 cam, dual plane intake, stock exhaust manifolds, 4 speed manual. Will be driven conservatively with the occasional spirited sprint down the on ramp, maybe 5500rpm max. Math works out to 459 cfm. I'm thinking about a 500 cfm 4 barrel...what do you think? Do you know if Holley makes a 500 cfm carb? Or would Edelbrock be a better choice in this case
In this case with a lighter car, I’d use a slightly larger carburetor. 600-650 would be just fine. Everything you have mentioned would match up well with that. Part of the issue with these formulas, they aren’t an exact science. 👊
@@StLouisSled all depends on what you’re going to do with the car. Drag race only? Holley. Street driving? Edelbrock. For what you explained, I’d lean towards the Edelbrock. Easy to tune and will be very friendly for what you’re doing with it.
500 to 550 sounds fine. My friend used a 600 vacuum secondary carb on his 65 Mustang with a 289. Keep in mind two thing. A manual transmission can help a car with too much CFM. When I was in HS, we built a 10.90 comp car at the winter nationals at the old track just outside of Phoenix, Beeline Dragway. We ran a 283 bored out to 292 cubic inch engine. It had a solid roller cam and a 1050 dominator. Again, running a manual trans would have helped, but this high winding screamer was backed by a 2 speed powerglide automatic. It took a good tuner to get that combination running well. We ran under the index in the final, losing a 10.89 pass to the other guys 10.94. Kind a hurts when you lose because you went too fast!
Interesting: The Holley website has a formula and also a little electronic tool where the data is entered and then you get an answer as to what size carb to use. Edelbrock has the same thing. HOWEVER Holley then says to take the cfm recommendation and add 15% to it, for whatever reason. Edelbrock doesn't say this. They just stick to the initial number that their little electronic tool spits out. Both websites do agree, though, on the fact that you have to be realistic in what rpms you're actually going to run the engine at. Don't tell the calculator that you're going to run to 6000 rpm (or whatever) and then actually you never go over 5000.
Awesome man Ty. I’m using 93 octane 1978 stock vette 350 and according to this a 650 is more than enough for street driving. I got a 670 avenger holley
Ford 302 bored 30 over manual going to use a t5 with 3.55 gears in a ford ranger. Looking for a torque cam and wanting to tow/haul with it and also just daily drive it. I was thinking a 600cfm would be great.
I'm thinking the melling 24110. Advertised intake is 282 and advertised exhaust is 298 with an operating rpm of 1,200 to 4,000. The factory cam is advertised intake is 283 and advertised exhaust is 273. Max rpm id go is probably 5,000 for either cam. And could you tell which cam would supply more torque at lower rpm?
@@cargeekscott1871 that is a very mild cam. Should be all in by 5000 rpm. Should be just fine with your combination. Just know that the cheap cams are typically valvetrain noisy.
Hello from Canada! I recently picked up a 1977 GMC Sierra K15 4x4. It's 98% complete. The previous owner dropped in a late model gen1 350 TBI and running gear from a 1987 Chevy Suburban. It's not running it was just placed in, nothing hooked up. I would like to swap out the TBI set up and put an aftermarket dual plane intake and carburetor on it, possibly headers I can't find any cam specs on this engine but do know it makes 200hp and 300 ft/lbs, At what rpm I don't know. Realistically this engine wont be seeing to much time at high rpm, probably 5500 max. I keep doing my calculations with a 350 ci and 85% VE and the number keeps coming up at or around 470 cfmchevy. This seems way small for a small block Chevy. It's a truck build and I'm looking at getting the Holley 90470 off-road carburetor. The website says recommended for 4cyl, v6 and inline 6 engines. Is this carb a poor choice or just what I'm looking for. The next size up in this series is a 670 cfm. Im in Canada and these carbs are going for just over $1000, I gotta get this right the first time. Your opinion and knowledge means a lot to me right now, thanks
The thing is if you’re not sure on the cam profile or you feel like a 500 CFM carb would be too small, then put on a bigger one. I can tell you at that Hp level and likely won’t spin that thing past 5000 rpm, I’d have no problem putting a 500 on. But like I said above, if a larger size will make you feel better, then go for it. You’ll know if it was the right choice or not if the tuning becomes difficult.
Howdy. Just found your channel, subscribed and will be viewing more episodes as time permits. I'm taking a bit of a backwards journey from the bigger, faster, louder way of thinking. Car is a 65 Chevy Two station wagon with a 350 topped with Edelbrock Performer RPM heads, intake and 1411 carb. I have removed the RPM cam and installed a Summit 214/224 mild "RV" cam, chucked the 350 turbo for a 700R4 and am currently rebuilding a 1406 carb for it. I drive it a lot and with fuel costs what they are, MPG is important. It cruises the interstate at around 2400 RPM, has 18 in. idle vaccum but still is lousy on gas. The 1406 has factory tune jets/ rods/ springs. Any suggestions? Anyone else shooting for more MPG not worried so much with ET anymore? Doing the math real quick, I come up with a 405 CFM being sufficient.
If fuel economy is truly what you’re after, a 500 would have been the better choice. But aside from that, the next video you should consider watching is ua-cam.com/video/vSfAbSH9NQk/v-deo.html
It’s the way the OEs have gone after the growing restrictions on economy. Keeping the operating rpm as low as possible will increase fuel economy. Less rpm means less fuel used. So a modern 6 speed would be an even better choice. You’ll see the largest gains in the trans. Welcome to the channel! Eager to hear how your quest goes for more MPG!
Just purchased 66 gmc believe it had stock motor and carb 305 v6 and strombreg 2 barrel wondering where I’d be able to buy a remanufactured carb possibly or how to figure out what aftermarket carb would fit on it just for daily driving
Last time I looked there wasn’t a heck of a lot available for those engines. They’re for sure different, but I’m not sure how easy it’s going to be if you want to upgrade anything. I’d have a builder go through the factory carb and leave it be. Unless you plan on swapping the engine to something a little more modern. Then all options are available.
I have a '67 Dodge charger, 360cid (sheet metal kits/better camshaft) I put an edelbrock CFM: 600 on it with an electric choke, it worked really well, then the electric choke broke, I didn't know you could buy a repair kit. I bought a new edelbrock 600, manual throttle, I've never gotten it to work well, the nozzles have been changed and sometimes too much petrol or too little, when I'm sitting in a wheelchair, I can't install it myself anymore, Finland has good installers for sure, but they're too expensive for someone on a small pension , would it be a replacement, for example, a holley double pump??
Don’t blindly change parts. Figure out the resin for the issues and fix it. Just mindlessly swapping parts/carburetors isn’t going to solve your problem. Finding the problem is a whole lot less money than the expense of buying an expensive new carburetor every time. I’ve got videos on all the issues you mentioned.
@@petskudahlman I don’t know. You didn’t provide enough info to make that statement. You watched the video? Based on what was in it, what CFM did you come up with?
I have a 350 chevy in an 1981 Chevy k10. I installed a new crate engine in it to replace a worn out 305. I used an Edelbrock AVS2 650 with electric choke. I have the initial timing set a 10 degrees BTDC. The issue that I am having is that when it is warm out and I turn it off, it is hard to restart and acts like it is flooded on restart after 20-30 minutes. I have not made any changes to the carb at this point. I put hedman hedders and glass pack mufflers on it when I installed the engine 3 years ago. So there is no catalyst now. OE fuel pump, no regulator. I'm wondering if the fuel pressure is coming up with a hot engine and leaking past the needle and seat. I have a thermal shield on the fuel line from the fuel pump to the intake manifold, Edelbrock thermal mounting gasket and the adapter to mount a carb. to a quadrajet manifold also. Thanks for any advice that you can give.
It sounds like the thermal gasket isn’t enough. Should have plenty of room under hood to run a thicker spacer. I did a video on heat soak and ways to help cure it. What you’re experiencing is common with the crappy ethanol and fuel we have today.
I'm running a hot setup on the street. It''s 468 big block Chevy with a 7,000 RPM range. According to the formula it equates to approximately 947.9 (950 cfm). As of right now I am running a 950 carburetor. Pretty much spot on. However, I'm running a FST 4500 series 950. My question, is there a big difference between 4150 style base plate, and a 4500 style base plate? The car loves the 4500 at high rpm.
I ran your equation on a ZZ4 Chevy motor , 350 x5800 /3456 = 586.3 CFM carb. Chevy documents for the carb calls out for 750 CFM Holley. I have a 600 CFM double pump Holley carb. I am assuming the 750 must be jetted down and my 600 jetted up. Kinda confusing.
You cant tune CFM. It’s a fixed number. You can however adjust fuel and spark to help tune the engine to its full potential. Are you using this as a drag only engine? Any other upgrades of significance? Nitrous? Boost? Then maybe... and that’s a big maybe, a 750 would work. Only if it were a vacuum secondaries carb. Like what was mentioned at the end of the video in other details to look at to confirm the right size. What are you using the engine/car for?
No it’s not a drag vehicle, I have a 1965 El Camino . It’s just a street Rod. I have an appointment with RPM carburetor shop to get it tuned, but I watched your video and ran your numbers for curiousty. Chevy 750 carburetor was most likely for drag car. Thanks
Well a street car is a whole different story. How often do you see 5800? If you’re just cruising, not often at all. You may see it if you’re doing some more aggressive driving, but unless that’s a common occurrence, you’ll never use the CFM that carb delivers. With a 750 it’s going to be very rich pretty consistently. There are a number of other things to consider but in very general terms, it’s all about assessing how you’ll drive it and those factors that are unique to your situation.
@@MuscleCarSolutions I have a ZZ4 in a 29 model A that I just got. It has a 750 on it now but leaking and I was going to replace it. The motor has a performer RPM manifold and edelbrock mechanical fuel pump.Was told it was a stroker motor. But I'm not sure. I was wondering if you think a Edelbrock 600 or the AVS2 650 would be best? Just a cruiser hot rod. Just trying to get it running right to enjoy.
The Holley Carby maths is 99% spot on every time, be it N/A or Blown carb applications. There's waaaayyyy too many over carbed street cars getting around with that " mystery" flat spot at WOT
it wasnt that it was too much carb. it was more of the TYPE of carb. but i know which episode youre talking about but they did another episode and a double pumper is obviously gonna flow more fuel. thats why they made 24 more HP vs a vac secondary of the same size. both flow 750 CFM. fuel curves are completely different. mechanical secondaries flow more on the secondary side . exactly why the double pumper is what it is, an extra shot of fuel,.
Thanks for the awesome video! I have a 289, uprated cam but nothing too aggressive in a 1931 Model A hot rod. Pretty light car, I would guess around 2200lbs and its a automatic. Currently has a 600CFM Edelbrock Performer and I’m thinking about moving to a AVS2. Its street driven with 91 pump gas. Thinking a 500CFM?
@@MuscleCarSolutionsI appreciate the reply! The car is new to me and the internals are unfortunately unknown. It has a very slightly lumpy idle and it still pulls well off idle which is all I know about the cam. My assumption is pretty mild but bigger than stock. I calculated with the assumption of 6500rpm.
@@349a4 so in this case, you can just go by how you’ll drive it. If you’re going to put it on the cams redline often, then yes use that rpm number to calculate your decision on a CFM size. If you’re not planning on driving it that aggressive, then you can use that number. If you go the second route and you have a situation where the math gives you a number in between two sizes, then go with the bigger option.
Brian, great video! I am working on my all original 1956 Ford Ranch Wagon, has the 292 V8 engine with the 3 speed manual transmission, it's a rebuild, but stock, nothing hi performance. I'm wondering which carburetor to go with, any advice? Thanks Brian!
@@MuscleCarSolutions 450-500 cfm The previous owner installed this cheapy 2 barrel carb., original carb was a 4 barrel, original carbs for the 292 can be costly
Hey your video are awesome, I’m learning every time. I just got a 1968 Chevelle with a 307 a 1406 and performer serie manifold intake is it too much? Runs nice at high rpm if I got stuck in traffic eddy gets flooded….I think
Hey mate, just putting together a fresh rebuilt mopar 360 with a mild cam 214/224 @.50 112 LSA. it has j heads and a dual plane air gap intake. Headers and 3:55 diff gears. Automatic transmission. It’s a weekend Cruzer and occasional burnouts 😉. What size cfm carb ? Vac or mechanical? What brand? That’s mate. 🇦🇺
That cam is likely all done around 5800-6500? Not familiar with the flow characteristics on this heads. If it’s oe from that era they flow ok but not great. For what you’re doing, what size did the math tell you?
@@orlando_mopar_srt interesting. I’d expect an LSA of 112 to push way past 5500. Either way, if the cam manufacturer says 5000, then I’d stick with that. In that case I’d opt for a 600 and a 650 at the absolute most. If it’s a cruiser, you can’t go wrong with the Edelbrock. AVS2 would give you the 650cfm you need. I’m sure there’s a retailer in your country. Sounds like a fun little car. Cheers!
@@MuscleCarSolutions Thankyou for the help and reply’s mate. Much appreciated. I will stick with the 650cfm. Do you think 650 vacuum secondary or mechanical? Cheers
Hi, love the content, I've got a 383 Chrysler stroked to 489, mild hyd roller cam and alloy heads, Thinking 750cc will be enough for street, auto 4 sp and 5500 max revs ?, thanks
Thanks, much, Mr. ... Picked up an old stock '70 318 Dodge W200 Power Wagon, truck gears, seldom over 3000 rpm, Carter BBD 2 barrel. .. Shop manager, & local mechanic suggested a low rise/ 4 barrel Edelbrock. Folks at Edelbrock set me up with matching manifold & #1405 600 cfm carb. ... questioned Edelbrock's service dept. about size of carburetor, & they qualified it. ... ... Just about to install. .. This video suggests I would make an incorrect/troublesome decision. .... Any knowledgeable input is welcomed.
They’re always going to go a size larger. It’s way better to be on the rich side than the lean side but in this case, if all you ever see is 3000 and below, the 500 would have been a better choice.
400 small block bored 30 over with small cam. Got a 750 cfm and a 600 cfm amdni camt seem to get either one adjusted to get the stumble out when the throttle is hammered down
Well. Start with the CFM. Which best fits your situation based on what the video showed? Next if verify initial and full timing. Then verify proper fuel system set up. Then you can start tuning.
Great video!! my application is a little different 350ci only turning 3000 MAX rpm on a airboat by your calculations a 500 cfm holly is more than enough. my question is i hear they make a 480 cfm holly 4 barrel would that be a better fit than the 500 2 barrel? Thank you in advance .
I have a 84 Silverado 3/4 ton truck with a 350 motor. Truck will be used for towing/hauling and weekend driving. It had an edlebrock carb when I got the truck but I want to upgrade it. Holley 600 or 650? What do you recommend?
Hi, very good explanation of how the carburetor works and how to do the math . I’ve got a 65 Olds Cutlass with a olds 403 .060 over, headers , olds 350 heads w 65 cc cambers 9.1 :1 , Edelbrock performer rpm intake, Carter 750 , isky 262 / 262 cam , stock rear ended , HEI TH2004r w lockup converter. Runs so so. I did the math and it looks like a could go with a 625 or a 650 CFM Edelbrock 408cid x 5000rpm 3456 = 590.2777 Any suggestions? Thank you for your time and efforts Job well done. Ernie
Kind of really depends on this one. I’d probably step up to the AVS2 and go with the 650. You’ll get some better throttle response with the annular discharge carb. Should have no trouble tuning it for that fun Olds motor. Big fan of any of the BOP engines and cars. 👍
@@MuscleCarSolutions thank you very much for your prompt reply and time . Always a pleasure to talk with someone who has been working with this kind of thing . I’d send a picture of my car but this site won’t let me . Take care and be well Regards Ernie
I was using a 1.08 Autolite 4100 on my 302 in my 78 Mustang ll, I thought it ran awesome.....until i put a Summit 600 cfm on it and it woke it up. I now have aluminum heads, BluePrint HP 9008's and a much hotter cam so I'm thinking a 750 might be more in line, it will see 7k rpms at times. I looked up a 302 boss (real) engine and it show it came with a 780 Holley. Your thoughts? I am a subscriber and I have learned a lot watching your videos.
If it’s a race purpose built engine and that’s where it’s going to operate. The 750 might be a bit much, but it will ensure your top end will remain rich. Given the small cubic inches and on a race engine, I’d run a 650 HP. Give some tune ability to the mid and high range circuits.
I'm guessing the 750cfm carb on my 305 low compression el camino is slightly oversized. It's a qjet the PO put on to replace the feedback carb it came with.
I have a 68 f100 long bed . Has a 390 bored .040 mild cam, headers aluminum dual plane intake, and exhaust. automatic transmission. Stock gear ratio. Just a street cruiser. Probably never see 5500 rpm. What are your recommendations.
Great video. I’m new to this and I’m hoping you can give me some guidance. I recently bought a ‘70 c10 that has a sbc 400 with a th350 trans & a 373 rear gear. As far as I can tell the motor is stock. According to some forums I read my trans should shift at around 4500 at wot. When I do the calculations I come up with 520cfm without using the Volumetric efficiency. I’m looking at an edelbrock AVS2 carb in either 500 or 650 cfm. Would you go with the 500cfm if you were just using the truck as a cruiser for the most part?
Because of the cubic inches, I’d probably opt for the 650. Especially with that rear gear. But the biggest question would be, are you planning on any upgrades in the future? Headers, intake, better ignition, etc. if the answer is yes to any or all of them, go with the 650.
Not planning any engine upgrades. There are lots of other things that need attention. I can’t say for sure if I will do some in the future or not. That being said do you still think the 650 is the way to go? When it comes down to it I guess what I am wondering is how much the throttle response will suffer with the 650 if no changes are made to the motor.
I have a mild cam. Aluminum heads. Performer intake. Roller rockers and headers on a 351w. With that calculation it says I should be running a 500cfm 😳. Every hotrodder I’ve talked says I need to go up in cfm. I have a 600 on it now.
@@averagebogarage everyone should experience at least once how an engine runs and wears with too big a carburetor. Sounds like you’re being pushed into that lesson.
@@MuscleCarSolutions not now. Lol. One more question and thanks for ur reply. Would u go w 500 in my case or stick w the 600. It’s just a toy I drive around town and get on every now and then I’d say never anything above 4500ish rpm. Which works out to 507 using that equation. So 500 or 600. In ur opinion? Thanks again
@@averagebogarage if that’s your upper limit on RPM, both will work, but the 500 will be very easy to calibrate and have much better throttle response. Really all depends on the cam specs and how you’ll operate it. I just put a 500 on a 496 a few weeks ago into a tow rig. Flawless.
I have a 400 sbc with dart iron eagle heads 2.0. ,xe 274-10 cam . I have a 750 dp quick fuel brawler. is this too much carb? you have been a godsent to me so far. thanks 70 primary, 80 sec 6.5 power valve. has a miss when secondaried come on.
That’s a a really good cam. 230/236 on a 110. Installed a ton of them. It’s all in by 6000 though but if you’re going to the track on occasion or aggressive driving, the 750 should be just about right.
I have initial timing set at 8 and total at 35. my manifold vacuum is only showing 14 hg inches at idle of 800 rpm. msd ready to run diz with va. I been chasing a bad stumble when you smash the throttle, bogs, spits sometimes backfires. I can ease into throttle up to 100mph but when I go wot it falls. muncie m20 4 speed. 69 Beaumont (Canadian chevelle). 3400 lbs. Could the 6.5 pv be too small or blown perhaps from all the backfiring? Appreciate any help.@@MuscleCarSolutions
@flyinhighaerial3193 couple things jump out here. 8° is not a lot of initial timing. I’m down close to sea level and start at 12-14. If you’re in Canada, I know you have some different fuel options so even if you’re running a fuel with no ethanol, add a bit more timing. Backfiring. The newer carbs have the check ball to keep the PV from being blown out every 2 minutes but it wouldn’t hurt to change it. I’d you’re seeing a stumble, you can try two things. Make sure you have the accelerator pump arm adjusted correctly and you can change the PV. If you want it to come in later and you’ve got the 6.5 in now, change it to a 5.5 and see if it gets better. Worse? Then it could be a lean condition. So go back up with the PV and try again.
Accelerator pump is adjusted. I did drive it for 5 miles to get home and it backfired plenty when I had a coil go bad a couple weeks ago. After seeing your vid on pv’s today I thought it may be the issue. Today after warming up to operating temp I closed the choke by hand to check for a vacuum leak and could close it entirely with no change in motor. Would that indicate my pv is blown?
It’s an interesting question. I know they are all a little different in how they are rated from the manufacturer. What’s interesting is when they are flowed with one manufacturers process, and you put another brand on that used a different process, you’ll get a different CFM rating. Doesn’t mean it’s wrong, it just means a different set of standards was applied in the rating. I’ve thought of doing that video but I don’t have a flow bench at my disposal.
So, what I have learned for example is that a Pontiac Bonneville with a 389 means that a 700 carb ain't too much because my numbers ended up in 714 point something.
Thank you for the knowledge but I wanted to ask to be sure I have a 1978 Ford F250 super cab 4x4 with a 460 4000 rpm would probably be my max rpm I'm looking for fuel efficiency more than anything daily driver if you could help me pick a cfm that would be great I run maybe 85 or 87 from the gas pump
Well, you have the key components there. What did the math tell you? Something to keep in mind here. If you really want better fuel economy, and this is something you’re driving frequently, you’ll find those big gains in the transmission, not the engine. I did a video on how to get better fuel economy in a muscle car a few years ago to illustrate how that’s possible.
Love the video. Would love some input on my situation. I have an 87 suburban with a mild 454 BBC. Mild cam, long tube headers. Running a 4 speed manual and it’s also on 40 inch tires and 4.10 gears. (needs 4.56) Just a cruiser/ off-roader that I never take above 4500 rpm. But I do live in the mountains with lots of decent grades where you really need to roll into the throttle to get it to move. I ordered a Holley 570 street avenger because of the low rpms I consistently run but I’m second guessing myself because of the load it sees with the hills and grades. Any ideas would be appreciated!
Awesome and enlightening video! I recently purchased a '67 GTO with a 400ci and Edelbrock 600cfm, intake and a 2004R w/od trans. Runs rough and runs on. I'm now running 93 octane and I'm thinking a Holley DP 750cfm and new TV cable/throttle setup. Am I on the right track? TIA.
Don’t know. What was the size CFM you got from the information in the video? What are you using the vehicle for? Drag only? Cruiser? What have you done to address the running issues you’re having? I’d be a lot more concerned about those before I made any carburetor changes.
@@MuscleCarSolutions I’m looking at 400ci at 6000rpm w/93 octane came to a 750cfm. Definitely a cruiser. I’ve run the higher octane and even tried Seafoam but to no avail.
When that thing was new, it probably ran great from the factory using a stock 750 CFM Quadra jet. I know gas today is not as good as it was in 1967, but the engineers at GM knew a thing or two. I would try a QJ.
Based on the information in the video, what did you come up with? If you watched it, you know that there’s not enough information given to make a recommendation.
@@MuscleCarSolutions the car make max hp at 4800 rpm 320 hp thats al i now i just bouth the car ful stock only want to change the carb en go whit a electronic ignition
@@jantienesstruyk3538 ok. So now you have the CI and the RPM and you can make a choice. Seems like a pretty easy decision. The 500 would be the best way to go.
Will a 750 (CFM???) Edelbrock for my soon to be machined /rebuilt 1970 472 V8 Cadi CDV (keeping engine as OG as possible and boring only)? I've been advised to go electric choke too, so will I need press. reg, and electric fuel pump too or can I keep my og mechanical fuel pump? Thanks for awesome Vid I think my calc for CFM = 601. [472 X 4,400]/3456= 601 This car will run. 91 gas, mostly cruzin to shows and with low riders, but want to drive say within 100 miles distance on freeway 70mph. Thanks again from Sunny SD, Cali. Cholo Clem
Love the video I have a 462 Chevrolet with Pro race right heads elder aluminum 850 cam max rpm 6500 my spark plugs go bad very quickly. Is this carbureted working properly Is it big thank you
Hello friend, very good video I have a 2600 cc montero, doing the calculations I get 160 inch and exploring the internet I have not found a carburetor that is offroad type with so little cfm, more or less it comes out at 220 cfm rated, if you had Any suggestions I would appreciate very much
Unfortunately you’re going to be limited to what other options might have been available on those smaller engines from the factory. I’m unfamiliar with the small engine sizes but the math still works the same. Though I’m not sure the factory replacement stuff was measured in the same way. Your best bet might be finding a Mitsubishi/Toyota/Nissan type of owners group and see what they are doing for those older carbureted engines.
4 scenarios. 1. 70 Torino wagon 351 Cleveland 4v. auto with 3.00 gears. All is stock. It has an EB AVS 650. 2. 71 Torino GT 351 Cleveland 4v. Auto with 3.00 gears. All is stock. It has an EB 600. 3. 71 Mustang Fastback 351 Cleveland 4v. 4 speed 3.25 gears. It has headers EB Performer intake 750 Holley Dbl Pumper. MSD distributor. 4. 73 Australian Falcon 71 351 Cleveland 2v heads auto with 3.00 posi gears. It has a Holley 600 with Edelbrock Performer. I have tri y headers to put on in the near future. Can I use a 780 Holley or 800 EB AVS on any of these in the above configurations? Do the 4v Cleveland heads come into play? Would 4v Big heads do better with a 650 at low rpms? Thank you.
Really you have to follow the formula in the video. Need to know your max rpm and go vehicle by vehicle and make the determination on the best size to go with.
@@kennethmarston8687 so pretty easy then if you follow the basic formula in the video. If you’re staying under 5000 rpm and mostly stock engines, go with the closest number to what you came up with.
First of all thank you so much for superb information regarding carburation. You have put my understanding of carburation to another level. Thanks again. I have aquestion for you thats puzzle me alot. I Have a '70 Cadillac Deville, stock engine (375 hp), stock TH400 and stock 2.94:1 rearend. Never passes, and never will, 5000 rpm. When the QJet came to age i put on a Holley 4160 600 cfm (0-80457s). I have a O2 sensor in my exhaust so i can check AFR. What puzzle me is that when passed idle i have almost perfect 14,7:1 AFR. But.... at idle, whatever i adjust or fiddle around with, it never go past 12.0:1. So my idle is a little rough and smell rich. Is there anything i am missing out when adjusting idle or do you have any idea why my AFR are so low in idle?
Yes I could use some help with my build, I’m building a 525 cubic inch motor, I’m using a Chevy big block 427 tall deck block 4.310 bore and 4.500 stroke, I bought 26cc dome pistons, use Brodix heads, either 345cc are 366cc, 119cc combustion chamber, I’m shooting for 1.7-1.8 HP per cubic inch, any help would be appreciated, thanks
I suppose you could start there. Maybe those folks had different ways of thinking about it back then. For sure the parts were different. Fuel was for sure different. Less access to lots of cam grinds and cylinder heads. But like the common math problem of today, it leaves too many questions unanswered.
Hi. I know this is an older video but I greatly appreciate it none the less. Hope I don't overload you with info here but.... I'm less confused after watching it but still wondering which way I should go, possibly because there are so many people running over-carbed motors and I can't seem to shake that. Anyhow, I have a 66 mustang fastback with a 72' 302 and C4 3 speed Auto. It was my Dad's years ago and I managed to buy it back... cool story actually. Anyhow, I have no idea what the cam is but It definitely sounds a little more aggressive than stock. I still get 18 hg at idle from manifold when tuning so its not a crazy cam. It also has dual exhaust with long tube headers, H pipe with flowmasters (40s I think) and currently has a Holley 650 Double pumper (List 4777-3) with mechanical secondaries. Stock mechanical fuel pump. Fuel I usually run is the shell v power nitro + 91 octane (10% ethanol I believe) with a bottle of lead substitute and Orielly's octane booster. I drive pretty conservatively and only cruise it. Will never see a race on the street or strip but I might stomp on it when getting on the highway. When I run the formula, 302 x 5000 / 3456, I get 436.92 CFM. Quck Fuel makes the HR-450, a 450cfm double pumper with vacuum secondaries and Summit makes the M2008 500cfm DP with Vac. secondaries. I guess I'm ultimately asking if that's the cfm area you think would be ideal (is 450cfm enough) and if you think either of these carburetors are a good choice. OR, what would you suggest? Again sorry for the napalm of information.
Very sluggish from the line but has plenty of top end power at 65mph highway speed. Idles rough for sure. Had the carb rebuilt and spent hours tuning it to get rid of the stumble it had on initial acceleration.
@@MuscleCarSolutionsNo, I tuned out the hesitation but it still idles rough and is sluggish. I thought maybe it was low compression but I checked all the cylinders and they're all in a good and equal range and there's no leakage from the valves if I let the gauge sit there a while, so compression is good. So I'm just thinking its over-carbed. Thought by dropping to a smaller carb I might get a smoother idle and a little more pep on the street. Just not sure how much lower I should go. My options are 450, 500, 570. Plus I'd like to keep the driver side fuel inlet as that's where I've got factory hard line running to and would be a cleaner look in my engine bay.
Thx for the vid! Do you think a stock 351 Windsor 2 barrel will benefit from the "big" Autolite 2100 from a 2 barrel 390? It's one venturi size above the stock carb. Stock cam street driven, FMX auto. It ist more about fiddeling around and finding the sweet spot set up for the car.
@@roywarren6275 I'd agree the intake can handle that, the cam can for sure and the CI of that big block sure can. How are you planning on driving it? Drag car? Street bruiser?
The car will be one weekend out of the month bruiser. 68 Camaro ladder bar set up. Like the reviews of the “QFT” carbs. Like the street Q but for better street use I like the QFT SS 850. Specs about the same for both carbs.
Hi, I just came across your channel while watching one of uncle Tony's Garage's videos. After watching some of your videos, I was wondering if you might be able to help me sort out an issue I'm having. Here's what I have. It's a 1 ton dually with a 454, a manual transmission, 670 street avenger and 4.56 rear end gears. The issue is a lean spot just before the secondaries open. I've tried going to a black spring which is the stiffest. It got rid of the lean spot, but I don't think the secondaries are opening. I went one step down to the brown spring which seemed help, but there is a slight lean spot still and I can distinctly feel the secondaries open. Also with the brown spring, at times I don't get a lean spot, but I can't say for sure the secondaries are opening all the way. I don't know if the lack of a hit is misleading me compared to when I get the hit after the lean spot. All this is going wide open throttle from a slow roll at about 1200-1500 rpm. My engine has peak hp at about 4200 rpm and I don't really ever go over that. When I go wide open throttle at say 2000 rpm and say 30 mph I can't say I ever get a lean spot. Im not sure what other options i have. Thanks for your video's, I've been enjoying watching them.
I’d stick with the spring that eliminates your possible lean spot. I wouldn’t worry about if they are opening or not. If they aren’t, it will fall flat on its face. It’s normal to have a smooth transition as they open and you want that! Sounds like you’ve done quite a lot to get it figured out to this point.
@@MuscleCarSolutions I haven't done a whole lot, just tried a couple springs and put a .035 squirter in from a .031, which I'm not sure was the right direction. It seemed to clean things up, but I did notice it goes really rich (10.0:1) when I lug the motor and go wide open throttle. I'm not sure if it did that before though. I went out and drove it again, I think there is considerable amount of power difference between the black and brown spring (brown spring is lighter) It sounds different too. It also revs cleaner and faster and doesn't sound like it's struggling so much to gain rpm. The air fuel ratio goes to a about 15.0:1 before the secondaries open all the way, it still pulls pretty good up to that point. I think im losing some power though. Would going from a 6.5 power valve to a 7.5 maybe clean up that lean spot or am I past the opening of the PV by time i get to the lean spot. I wish incould watch the vacuum gauge at same time as the AFR gauge. Any thoughts would be appreciated even if you still think I should stick with the heavier spring.
I’m having my 5.3ls rebuild with a mild cam heads all that good stuff. Thinking of switching to a high performance carburetor. What size should I use. I think I have a 650 double pump on it now
Got a Ford 300 that i plan on keeping the internals mostly stock, just playing around with porting and cleaning up the factory manifolds, in your experience are the 1 barrels that came on these engines decent or should i ditch it for a smaller 2 barrel?
Boy I’ve had great luck with the 300s in the past. No kidding. I drove a cargo van from Dallas to KC with the factory one barrel zip tied onto the manifold. Somehow they vibrates loose and was stuck on the side of the road and zip ties to the rescue. Honestly unless you’re really make some big changes; cam profile, CR, you’re likely going to be ok with the factory carb. If you get into those areas, that’s when I’d look at a slightly bigger carb.
Well, ignore the intake that’s mismatched to your combo and tell me what number you came up with in the equation? It’s usually very close to what size you’ll actually need.
Thanks for the response.. I’m getting 575 cfm by plugging in 468 cubic inches and max rpm of 5000 on a few different carb size calculators so my 750 is way too big .. the intake was on the motor when I purchased it and not sure the cost to replace it is worth it …. Also I’ve heard that edelbrock carbs flow less cfm than Holley of the same size .. any truth to that
73 dodge w100 360 4 speed manual. Currently a stock 1987 360. I do plan on a slightly bigger cam. Like a 340 grind. I have a 600 cfm eddy which I think is a good fit for where I want to be. It's a daily truck and I work it a bit. If I do either equation it points me to a 500 cfm carb. However with the cam in the future I think the 600 will be perfect. What do you think?
I’ll almost always plan for future use. So if the future calls for a bigger size, and you can make it work on what you’re currently running, that has always been the best option for me. No need to spend money twice if you don’t have to.
@@kuhndog-1196 could be. I don’t know the specs on the cam or what the rest of the set up looks like. The 360 in that truck is a fairly low rpm engine, yes? That would be the biggest factor in making the decision.
Incorrect. Using a larger size will need the air speed through the venturi and booster to get the fuel flowing as the carb was designed. If you run too big a carburetor, the speed isn’t there to meter the fuel correctly. Running the correct size for the application is always best. Doesn’t matter the design of the intake.
I have a 1978 c3 corvette L-82 silver anniversary edition. I would like to upgrade the carburetor. What size cfm carb would I need and if I upgrade the air intake manifold am I able to choose any one? Ideally I would like to go fuel injected but I am not sure if I have to add an ecu or not.
@@FrankPung the trouble corvette owners universally experience is lack of under hood space. The only manifold that Edelbrock offers that will fit under that hood is the Torker and honestly, it’s not a very good intake. It is low profile however but it’s a low end power stealer. Lots of folks use them, but be prepared to lose some 2500 rpm and lower power. Yes, all aftermarket fuel injection systems have a computer to control the fuel and spark. They’re not very complicated, but you need a good installer that’s competent in that type of work or time on your own to learn how to get them set up right and how to correct any issues the system may experience.
What size carb and what type of carb would be best for a 4×4 off-road truck with a Ford 408W stroker? 6000 max rpm manual transmission 3.55 gears. The truck weight is about 5000
That’s a good one. As the mathematical answer falls at an uncommon number. So you’re using it as an off roader. You should have a cam profile and intake that is around idle-5500 rpm. If that’s true, then the off road 650 Edelbrock would be perfect.
Thanks for the content! I’m building a factory five car. The final weight is going to be about 2200lbs. I’m running a 347 sbf with a 5500 redline it’s going to be a purely street car. It’ll be mated to a tkx and irs with 3.55 gears. The math leads me to a 550 cam carb. Is that a good choice or would you recommend something else?
@@Doclittle1036 I did a video on the things I don’t like about it. Others have had success with them, but to me they aren’t worth the effort. It’s my bias, but I tried to give all those details in the video and the viewer can decide if it’s worth it or not.
I'm so lucky that you used the 351W as an example, since that's what I'm building! Is "Operating RPM" the same as "fast idle RPM"? Ford shop manual states fast idle RPM @ 1400. Seems very low, compared to 6,500.
Operating RPM generally refers to the zone in which the best power is made. If the set up was chosen to work together, the range is easy to determine. Most go by what the cam is rated at. It’s become a universal term of where the vehicle will be driving. Race car, high rpm. Street car, low to mid range and majority of the time.
Great video, im running a 9.8:1 383 stroker, 93 octane pump gas, auto, 3.73 and a fairly lighter car(80 malibu) the engine makes around 450-470 hp, engine builder recommended a 670 brawler( which he sells). Ivr had hell tuning this thing, i consider myself pretty knowledgeable on carbs but what size carb do you recommend. Everyone instantly says get a 750. Its a street car, but i do twist it to 6500 occasionally. Cam is 231/236 @50, 490 510 lift. Petronix ignitor iii ign, 1 5/8 longtubes, 2.02 1.6 ,aluminum heads 180cc runners, edelbrock air gap rpm intake.. I prefer vac sec for the street. Any suggestion? Im looking at Q series 750, or 750 brawler vs. What ya think?
@@lit549 in that instance, it’s usually the best thing for the engine to go to the bigger CFM. In this case, absolutely that’s where I’d go. 750 should be your better choice on this set up.
@@lit549 and your gurgling video is pretty common with ethanol gas. It’s boiling in the bowls. Check out my heat soak video to cure that. ;) Bonus tip. lol You have comments turned off on the video or I would have left it there.
You’re in a very difficult spot then. The only way you have left if to define how you’re going to drive it and define what your max rpm is. Then it’s a matter of living with your choice and tuning for that situation.
Thank you for such an informative video!
I’ve been telling guys since the early 80’s that you have to spec your components for what you want out of it.
They always said bigger is always bigger and you have to chrome it, etc.
I’ve grown up trucking in my blood with the family business. Every truck is different and has to be spec’s out for different applications. If you spec it wrong, it will not be able to do what it was intended for and you can’t make money from it. It will end up costing you more money just to operate if at all.
You explained it very well. You have to first figure out what you want out of it and go from there.
That is why so many guys go and buy that dream car and end up crashing it moments after picking it up. You have to know what the vehicle is capable of doing and what you are capable of doing also. Once you get all the parts of the equation down, you will have a near perfect machine!
I say near perfect because we are never satisfied once you start down this road. lol!
Thanks!
Thank you! You bring up lots of good points. I like to take as much guess work out of things. If you can at least have a process, you can anticipate the results.
Even before seeing this, I believe most guys have too much carburetor on their engine. 750 cfm seems to be the default carb everyone uses, but I chose a 600 cfm for my bone stock 396 325 hp big block. The street manners and throttle response are impressive, better than any of my injected engines in fact. I've had many guys tell me I need a 750, that a 600 is too small etc. but nope.
Really all depends on what you use it for and what it’s set up for. I worked on a set up this morning that was WAY over carburated. I offered to tune one of mine on his set up to prove it. It really common and like you mentioned, doing it right will get you a better running engine. Thanks for watching!
Interesting, anybody's 350 cid V8 at 5000 rpms only needs around 375 cfm, maybe 400 cfm at 5000 rpms, and most street cars never go to a higher rpm than this. Yet most guys never go lower than 650 on a carb, and many go to 750. We need to be realistic when we enter data as to what the revs are going to top out at.
@@bobkonradi1027 and the factory carb was a 750.
The factory carb was a 750 Q-jet, the 350 hp 396 had a 750 holley carb.
True. It’s easier to pick one carburetor and put it on everything than to switch it up. Doesn’t mean the engine is using all 750 cfm. They put 750’s on 305’s and the secondaries wouldn’t even open all the way even at 5500 rpm.
I just let your video audio Play in the shop when I’m working and not in the mood for music. It’s great background noise that also refreshes knowledge
Nice! That’s pretty cool actually. 😆 I’ve always wanted to be background noise! Thanks for the laugh. I really do appreciate that and glad you found a way to listen. It’s a great idea! I might start doing the same.
Few weeks ago Brian helped me work through picking the proper fuel delivery for a project I'm working on; very nice and knowledgeable guy. Thanks again Brian.
Best of luck with your project!
I just had an "Ah-ha!" moment at @16:10 . It took me a couple runs through your other good videos. U never know what you missed when you don't understand stuff. Thank you, again!
Nice! Well I hope you got the answer you were looking for! If not, just ask and we’ll figure it out. ;)
@@MuscleCarSolutions Thanks! Yeah. I'm trying to piece how it all works. Fun to learn. 👍 I'll have more ?s down the road...har har...
@@stuckinmygarage6220 all good! I’ll be here!
When towing or using engine in a heavy vehicle go smaller CFM. Air Velocity is what we are after in carburetor sizing. We want high air velocity so the carburetor works properly plus to fill the cylinders well especially at low rpms. If air velocity falls off due to carburetor being to big low end suffers. That's why smaller for towing and heavy vehicles. You can go bigger with lighter vehicles and higher rpms engines. When driving on the street we don't see much past 3500 rpms so the high air velocity of a smaller carburetor provides a much better driving experience. Good stuff!
Quality comment, thank you Cliff !
I had a '77 Camaro back in the mid to late 80's that had a .40 over 350 with flat top pistons, roller rockers, stock exhaust manifolds a TH-350 trans, stock converter with 3:08 rear gears and 305 two barrel heads with small ports and an RV type camshaft ( I don't remember the brand name or specs on it though) that had an almost stock idle but you could tell it wasn't completely stock, the intake was a dual plane Edelbrock performer and I put on a 600 Holley with vacuum secondaries. I dont remember if the Edelbrock carburetors were around yet but the Holley was just over $100 brand new back then. I never had to fool with the jets or anything other than the idle speed and mixture, it ran pretty well out of the box. I ended up daily driving that car for quite some time. I had to watch the fuel quality and timing since the 305 heads bumped up the compression a bit but it had excellent throttle response and averaged around 17 MPG on the highway. I'm sure the cam, heads and exhaust held back any real top end performance but the low end torque was good enough for what I used the car for since it rarely saw anything over 4-5K RPM. I still regret selling it along with the other old cars I used to have which were cheap and plentiful back then.
Thank you for the great video. I am trying to find the best carb for my 77 CJ7. It has the IL 258 with a mild low torque cam (I don't know the specs), Offenhauser four barrel intake, electronic ignition and headers. This Jeep gets limited use, but is used both off-road and street. Definitely not high rpm street racing obviously. Carb must be able to handle off road hill climbing without cutting out. I am leaning towards possibly a two barrel 350-400cfm carb with an adapter to the 4 barrel manifold. Any suggestions? Thank you
@@bryangalvin4205 off road applications can get tricky. You know what situations you’ll be putting this into. I would agree the smaller CFM carb would be your best bet. Depending on the HP level, you might also consider a TBI efi set up. That would be your best bet depending how extreme your off road adventures are.
Just ran across this video. It was VERY informative. Here is my dilemma: I have a stock 350 sbc in a 72 Impala coupe (weighs about 3900 lbs.) with a 200R4 transmission and 3.73 rear end. An Edelbrock 1406 (600 cfm) sits atop a dual plane intake manifold that is fed by in-tank pump (max psi: 49-50) regulated to 5.5 psi by an AER fuel regulator. Max RPM for the engine is 5500; however, I have yet to hit 4000 even on the hills in my locale (3800 was the highest so far). I do not race but use the 3.73 gears for acceleration and the 200's OD to cruise. The 1406, IMO, burns too much gas. Edelbrock recommends the 1406; however, an older mechanic I know suggested moving to the 1404 (500 cfm). The math in your video also supports that mechanic. I'm looking for a final confirmation prior to spending the money for a new carb.
If you’re only spinning it to 4000 rpm, then that’s your number. Make the switch to a 500 and then TUNE it for your application. It’s not correct right out of the box. Never is. Once it’s tuned, then you can determine if it was the right move. Sounds like it will be.
@@MuscleCarSolutions thanks for the IMMEDIATE response 👍
@@ernestadamsjr.2662 sure thing. Best of luck with it! My family had a 72 Impala sedan when I was a kid. Love those cars!
If anybody is wondering the 3456 comes from converting cubic inches to cubic feet and from considering that the car is 4 stroke meaning you will only pull air every other rotation.
Then it means you need to half these numbers when using a 2-stroke carb. Or am I wrong?
I did wonder, ty.
Man iv follow you. I got a 350. 1972 Monte. It's a cruiser. But she likes to go fast. I put the fuel just like you I'm sitting at 5000 in Colorado. Adjustments made according to the chart. Still runs rich rich
thanks for clearing alot of this up, I have been looking for a Holley DP for my 466 BBF in my 78 f100 street/strip truck (mostly street realistically), have been concerned about going to little or wasting time over carbureting
It’s a common mistake. It’s easy to say go way bigger and think it’s better than finding what the need of the engine is.
I'm running a junkyard low compression dodge 360 , edelbrock 340 manifold , A body manifolds true dual in a 3300 lb car and 373 diff with a edelbrock 600 cfm , mostly in town driving . Runs great , amazing fuel mileage and spark plugs are a light brown .
I have chevy small block what size is best for saving fuel?
Lol, here I am again listening to your videos. Just put all the side markers in my Mach 1. A tie rod end. And adjusted my reverse band all while listening to these
Appreciate that! Hopefully there was something in there you found useful. 69 or 70 Mach 1 is a bucket list car for me. One of these days!
My car has the hated 301 and is factory turbocharged with an 850 cfm carburetor from the factory and it works great, it is a small turbo not a high horsepower engine it doesn’t run rich and it has a perv valve I believe is called that helps with the fuel mixture. Great video. Carburetors are a mystery.
@@Zelaznogsiul-63 it’s a spreadbore carburetor. It’s not flowing 850 CFM all the time.
@ I am more confused now. May be you could make a video about it, that would be great. Thank you for the reply.
@@Zelaznogsiul-63 Google spreadbore quadrajet and look at pictures of the base plate. You’ll see just how small the primaries are.
First - Thanks so much for all your Wonderful Video's. I've never been very well versed in Cars/Working on them. But have just acquired a new care "to me" and have been trying to learn about Carbs and
how they work and how to work on them and your video make thing very clear and understandable even for a 71 yr old Rookie ;-)
So, I have a 1990 Chevy 383 Stroker Motor, in a lightweight car (2700lbs) not sure of any of the internals with the exception Of
it came with documents for an Isky Mega 280 Cam, and it has an Edelbrock 1405 that has had an
Electric Choke added at some point. I did check the Metering Rods and they are the .070 x.047. I've been learning about the timing and have 18 deg Adv and 34 in at about 2500rpm. Hope this is enough information to be able to make some suggestions.
Thanks again, Take Care,
CK
Glad you’re enjoying the videos! So the root question here is the 600 the right carb for the 383 in a light car. First things first. We have to ask the question, “what are you doing with the car”? Just a fun cruiser or something more aggressive? I don’t know a thing about the specs on that cam but I’ll assume they’re around 230 and a fairly tight LSA. 107? That cam is likely going to be done by 6500, so now we know what the max rpm is. The rest is simple from the video. On a lighter car, a little more CFM isn’t a bad thing. If you’re going to work in the power band of that cam (if my assumptions were correct) then a 750 would be a great carb for that set up. Just have to make sure the rest of the engine combination match and you’ll have a screamer of an engine!
Hi,
Thanks so much for the reply and information. I'm just going to be cruising around in it on Nice Sunny Days. I think all in at 6500 is probably all my Heart can take ;-) Appreciate everything, Take Care,
CK
@@CKirk2727 I just found that cam. It’s not going to be a lot of fun for a cruiser. It will sound good, but it’s going to be down on power below 2500. Not very fun. I’m assuming that’s what you’re after though. In which case, the 600 might be ok.
Hi, LOL I had that feeling even with the short amount of time I've had it and driven it.
BUT It is what it is, at least now I know and so that will make things a lot clearer on it's performance, and drivability, and makes me feel a little better about my driving and tuning attempts. Thanks so much again for all your Help and the Great Video's I've learned a lot !!!
Great video by the way very informative for people such as myself.
My truck has a 700r4 tranny and the axel gear ratio is unknown at the moment.
Hi there so I have a 78 bronco with a 460 out of a 70s motorhome. Can’t get it to run fast and efficient lol what carb do you recommend. Currently has a 750 with Edelbrock dual plane manifold
Not sure I understand what you mean by fast and efficient. What is it doing that you don’t like and how have you attempted to tune it? What size did you come up with after watching the video?
Q-jets use the airdoor to tune the cfm.Everyone of them has at least the 750cfm potential i.e. of some rare buicktypes. The factory used the angle of the airdoor for setting the carbs to tamer or smaller engines
Correct but my understanding and experience with them since I was a young man..2 types 750 and a 800 CFM..Look down the secondary if thier is a nub sticking out.. It's a 800 CFM...looks like the tip of your pinky finger..Other wise smooth it's a 750
So glad I stumbled across this. I'm building a 351w for a 92 f150 4x4 AOD transmission. I'm running a .513 lift 270/276 duration 110 lobe separation roller cam. Stock Gt40 heads with a spring kit an edelbrock performer intake. Motor will be natural aspiration. Cam is rated 1500- 5500 rpm and intake is idle - 5500. It will be a daily driver and toy hauler. I have an edelbrock 1405 600 cfm sitting my shop now, but im wondering if I should step up to one of the new avs 650 cfm. Great content btw.
I’m glad you found it too! I don’t think you can go wrong with the AVSII. Sounds like for what you’re doing the 650 will be exactly what that combination is calling for. The windsor engines are exceptionally versatile and should deliver everything you’re asking from it!
I built a 351w 0.030 over 9.6.1 with a typhoon hi rise Intake. I also am running the same roller cam and I put it in my 87 f150 4x4 with a C6 and 3.55 gears. I have tried a 750, 725, 600 and currently using a 570 (all carbs are Holley) so far I think the 570 works the best.
Great info as usual! Appreciate all the knowledge you share with the car community, it really really helps!! Thank you and cheers from Motown. Oh, new subscriber and hit the bell.
Nice! Thanks for that. Just years and years of being around it and making many mistakes. Glad you’re here! Don’t hesitate to ask any questions. I try to answer them all. Motown thawing out and summer is almost there!
@@MuscleCarSolutions We have hit over 80 this week and set records. Scrambling to get my Mustang full spool out and go with a LSD so I can turn the darn thing. Also struggling with Deadhead or Bypass regulator. Probably Deadhead with gauge port Holley 12-840, if any problems will do bypass over winter. Mild built 460, RPM performer, Holley 4160 750,MSD 6al, C-6 manual valve body, full headers, 3" into magna flows, nodular 9" 4:11 gears, 4 link, was ex 8 sec race car, streetable now. Thanks See ya soon.
@@robertclymer6948 sounds like a heck of a fun ride!
Thanks for mentioning the dump truck engine. I’m I’m the beginning stage of planning a rebuild of a Ford 460 for a stake body that it’s sole purpose is to haul firewood.
Not much information about building high torque low RPM work engines.
Yup. Every year I get quite a few low rpm, high torque applications to help select components for. Dump trucks, yard dogs, logging trucks. Lots of gas powered stuff out there. Surprising how small a carb will work for a 460 when you’re only turning it less than 4000 rpm. Good stuff! Thanks for stopping by!
I had a slant 225 ran a 600 double pumper on it ran like a dream with the 4 speed manual
The ole pig rich, but it still runs so it must be right theory!
Love your content, I have an 86 cutlass supreme with 307, nothing else done. It would not run with the q-jet, so a friend gave me a 1406. Not looking to race, just have a little performance and decent gas mileage. I think this 1406 is way too big and getting about 10 mpg, where I used to get 20 mpg with the q-jet. Again love your channel and thank you.
Yup. 600 CFM on a 307 is over carbureted. Get a 500 and tune it. Thank you! Glad you’re enjoying it.
@@MuscleCarSolutions great thank you, which 500 do you think; 1901
@@GrandeTime yes go with the AVS2. Either manual or electric choke - your choice.
i had a carter AFB 500CFM carb 20 yrs ago on my 80 impala sports coupe and that had what they called an "Rv cam" 204/214 duration @ .050 and that was more than enough had the stock freeway gears stock heads and i found a cast iron 4bbl intake
70 chevelle 10:1 383 230-240 , advertised 280-290 duration, 489 int lift, 519 exhaust, rpm air gap intake, header and full 3' exhaust, th350 2500 stall and 3:42 gears.
I got an 350 small block hard to find a carburetor here I need a lil help
@@xpirxtion same here.
@@ricardssamuls9152 what's the application?
Great video, alot of guys over cam & over carb their street engines......I am building a 350 Vortec and I picked up a used 600cfm Edelbrock Performer(gonna do a rebuild on it just to be safe). This entire engine is being designed around that 0-5,000 rpm street tourque band. Scored a dualplane non airgap intake. If/when I change the cam I am going for a tight LSA (probobly 108) with a 0-5,000 appropriate duration etc. I am all about that throttle response since I am gonna spend waaaaay more time at 3,000 rpm vs 6,000rpm.....heck I am gonna roll manifolds since headers are a nightmare. Hp/cu-in in a light weight 2wd GMC Jimmy is gonna be FUN.
Thanks so much for the info . I have a 460 that I want to put an Edlebrock carb on .
425 cadillac bored .600 due to cylinder wall damage, so 439 Cid. Stock cam. Dropped into a 64 Buick LeSaber with 3.42 rear gears. Max rpm before valve float is 4500 rpm. Torque peak is 2000, horsepower peak is 4200. I honestly thought the car had had higher rear gearing, but it was originally a manual car with a 300 Cid v8. They all got deeper rear gears. 2000 rpm is 50 mph. Top speed is 107 before valve float shuts it down. Car is primarily a weekend cruiser. I have a 750 cfm Edelbrock on it. Original carb was a 800 cfm Quadrajet.
The Qjet can be a little deceiving when you just look at the CFM number. Yes it capable of 800 CFM but I’d you look at the primaries, they are in fact substantially smaller than the secondaries. It’s how GM wanted to control the fuel and give the air and fuel needed when the demand was needed. The difference in the two carbs really can’t be compared on CFM alone. But you certainly have a lot of cubic inches to feed if you decide to go bigger on that cam! Awesome to hear you’re running a big Caddy. Always fun to see those big old school engines still on the road!
@@MuscleCarSolutions Thanks for the reply. I got the Caddy and TH400 behind it pretty cheap and went with it. It's been fun, but frustrating at times. Partly because I chose a car that isn't common, and an engine to swap that isn't common, either. I'm considering upgrading to a mild cam and stronger valve springs to go to 5000 rpm.
@@johnbutler1323 that’s the downside of the cool factor. Fewer things available for their engines that don’t have a lot of volume to support lots of aftermarket parts. Which just makes what you’re doing even cooler!
@@MuscleCarSolutions Thanks. One of the crazy things about the 425 Caddy is they debored the big 472 from 4.3" to 4.082" and kept the same 4.06" stroke. When they did, they knocked off every ounce of excess metal in the block and heads and actually opened up the water jackets quite a bit. The 425 Caddy big block weighs 100 lbs less than the 472 it's based on, putting at 525 lbs, which is 50 lbs lighter than a fully dressed Chevy small block with iron heads and intake and comes out about even when the Chevy small block has aluminum heads and intake. It's a very light engine for its displacement, especially considering it's all iron. The block is so light, I could pick it up and carry it around when it was stripped. It does take up a lot of real estate, though, and is every bit as wide as a Ford mod motor.
Putting together a 289 Ford engine in a tiny 2500 lb Sunbeam Tiger. Small 270 cam, dual plane intake, stock exhaust manifolds, 4 speed manual. Will be driven conservatively with the occasional spirited sprint down the on ramp, maybe 5500rpm max. Math works out to 459 cfm. I'm thinking about a 500 cfm 4 barrel...what do you think? Do you know if Holley makes a 500 cfm carb? Or would Edelbrock be a better choice in this case
In this case with a lighter car, I’d use a slightly larger carburetor. 600-650 would be just fine. Everything you have mentioned would match up well with that. Part of the issue with these formulas, they aren’t an exact science. 👊
@@MuscleCarSolutions Thanks! Do you have a personal preference between Holley and Edelbrock?
@@StLouisSled all depends on what you’re going to do with the car. Drag race only? Holley. Street driving? Edelbrock. For what you explained, I’d lean towards the Edelbrock. Easy to tune and will be very friendly for what you’re doing with it.
500 to 550 sounds fine. My friend used a 600 vacuum secondary carb on his 65 Mustang with a 289. Keep in mind two thing. A manual transmission can help a car with too much CFM. When I was in HS, we built a 10.90 comp car at the winter nationals at the old track just outside of Phoenix, Beeline Dragway. We ran a 283 bored out to 292 cubic inch engine. It had a solid roller cam and a 1050 dominator. Again, running a manual trans would have helped, but this high winding screamer was backed by a 2 speed powerglide automatic. It took a good tuner to get that combination running well. We ran under the index in the final, losing a 10.89 pass to the other guys 10.94. Kind a hurts when you lose because you went too fast!
@kennethcohagen3539 I remember beeline in the 70s. Left PHX 20 years ago. Would run out there as an adult just to remember my youth
Interesting: The Holley website has a formula and also a little electronic tool where the data is entered and then you get an answer as to what size carb to use. Edelbrock has the same thing. HOWEVER Holley then says to take the cfm recommendation and add 15% to it, for whatever reason. Edelbrock doesn't say this. They just stick to the initial number that their little electronic tool spits out. Both websites do agree, though, on the fact that you have to be realistic in what rpms you're actually going to run the engine at. Don't tell the calculator that you're going to run to 6000 rpm (or whatever) and then actually you never go over 5000.
When I was a kid, the math was, max rpm x ci displacement ÷ by 3456 = cfm flow of engine. Add 10-15 % for low gear ratios low vehicle weight ECT.
Awesome man Ty. I’m using 93 octane 1978 stock vette 350 and according to this a 650 is more than enough for street driving. I got a 670 avenger holley
Sounds like a good choice!
600 Edelbrock on that, I bet that Avenger gets horrible mileage.
Ford 302 bored 30 over manual going to use a t5 with 3.55 gears in a ford ranger. Looking for a torque cam and wanting to tow/haul with it and also just daily drive it. I was thinking a 600cfm would be great.
If you’re using a smaller duration cam that’s typically all in by 5000-5500 RPM, the 600 or new 650 AVS would work just fine for that application.
I'm thinking the melling 24110. Advertised intake is 282 and advertised exhaust is 298 with an operating rpm of 1,200 to 4,000. The factory cam is advertised intake is 283 and advertised exhaust is 273. Max rpm id go is probably 5,000 for either cam. And could you tell which cam would supply more torque at lower rpm?
@@cargeekscott1871 I’d need to see the specs at .50 to know which would be better on the low end side.
@@MuscleCarSolutions the stock is 186 intake and 197 exhaust and the melling 24110 is 210 intake and 211 exhaust
@@cargeekscott1871 that is a very mild cam. Should be all in by 5000 rpm. Should be just fine with your combination. Just know that the cheap cams are typically valvetrain noisy.
Hello from Canada!
I recently picked up a 1977 GMC Sierra K15 4x4. It's 98% complete. The previous owner dropped in a late model gen1 350 TBI and running gear from a 1987 Chevy Suburban. It's not running it was just placed in, nothing hooked up.
I would like to swap out the TBI set up and put an aftermarket dual plane intake and carburetor on it, possibly headers I can't find any cam specs on this engine but do know it makes 200hp and 300 ft/lbs, At what rpm I don't know.
Realistically this engine wont be seeing to much time at high rpm, probably 5500 max. I keep doing my calculations with a 350 ci and 85% VE and the number keeps coming up at or around 470 cfmchevy. This seems way small for a small block Chevy.
It's a truck build and I'm looking at getting the Holley 90470 off-road carburetor. The website says recommended for 4cyl, v6 and inline 6 engines. Is this carb a poor choice or just what I'm looking for. The next size up in this series is a 670 cfm.
Im in Canada and these carbs are going for just over $1000, I gotta get this right the first time.
Your opinion and knowledge means a lot to me right now, thanks
The thing is if you’re not sure on the cam profile or you feel like a 500 CFM carb would be too small, then put on a bigger one. I can tell you at that Hp level and likely won’t spin that thing past 5000 rpm, I’d have no problem putting a 500 on. But like I said above, if a larger size will make you feel better, then go for it. You’ll know if it was the right choice or not if the tuning becomes difficult.
Howdy. Just found your channel, subscribed and will be viewing more episodes as time permits. I'm taking a bit of a backwards journey from the bigger, faster, louder way of thinking. Car is a 65 Chevy Two station wagon with a 350 topped with Edelbrock Performer RPM heads, intake and 1411 carb. I have removed the RPM cam and installed a Summit 214/224 mild "RV" cam, chucked the 350 turbo for a 700R4 and am currently rebuilding a 1406 carb for it. I drive it a lot and with fuel costs what they are, MPG is important. It cruises the interstate at around 2400 RPM, has 18 in. idle vaccum but still is lousy on gas. The 1406 has factory tune jets/ rods/ springs. Any suggestions? Anyone else shooting for more MPG not worried so much with ET anymore?
Doing the math real quick, I come up with a 405 CFM being sufficient.
If fuel economy is truly what you’re after, a 500 would have been the better choice. But aside from that, the next video you should consider watching is ua-cam.com/video/vSfAbSH9NQk/v-deo.html
It’s the way the OEs have gone after the growing restrictions on economy. Keeping the operating rpm as low as possible will increase fuel economy. Less rpm means less fuel used. So a modern 6 speed would be an even better choice. You’ll see the largest gains in the trans. Welcome to the channel! Eager to hear how your quest goes for more MPG!
Just purchased 66 gmc believe it had stock motor and carb 305 v6 and strombreg 2 barrel wondering where I’d be able to buy a remanufactured carb possibly or how to figure out what aftermarket carb would fit on it just for daily driving
Last time I looked there wasn’t a heck of a lot available for those engines. They’re for sure different, but I’m not sure how easy it’s going to be if you want to upgrade anything. I’d have a builder go through the factory carb and leave it be. Unless you plan on swapping the engine to something a little more modern. Then all options are available.
I have a '67 Dodge charger, 360cid (sheet metal kits/better camshaft) I put an edelbrock CFM: 600 on it with an electric choke, it worked really well, then the electric choke broke, I didn't know you could buy a repair kit. I bought a new edelbrock 600, manual throttle, I've never gotten it to work well, the nozzles have been changed and sometimes too much petrol or too little, when I'm sitting in a wheelchair, I can't install it myself anymore, Finland has good installers for sure, but they're too expensive for someone on a small pension , would it be a replacement, for example, a holley double pump??
Don’t blindly change parts. Figure out the resin for the issues and fix it. Just mindlessly swapping parts/carburetors isn’t going to solve your problem. Finding the problem is a whole lot less money than the expense of buying an expensive new carburetor every time. I’ve got videos on all the issues you mentioned.
@@MuscleCarSolutions is the edelbrock 600 the right size?
@@petskudahlman I don’t know. You didn’t provide enough info to make that statement. You watched the video? Based on what was in it, what CFM did you come up with?
I have a 350 chevy in an 1981 Chevy k10. I installed a new crate engine in it to replace a worn out 305. I used an Edelbrock AVS2 650 with electric choke. I have the initial timing set a 10 degrees BTDC. The issue that I am having is that when it is warm out and I turn it off, it is hard to restart and acts like it is flooded on restart after 20-30 minutes. I have not made any changes to the carb at this point. I put hedman hedders and glass pack mufflers on it when I installed the engine 3 years ago. So there is no catalyst now. OE fuel pump, no regulator. I'm wondering if the fuel pressure is coming up with a hot engine and leaking past the needle and seat. I have a thermal shield on the fuel line from the fuel pump to the intake manifold, Edelbrock thermal mounting gasket and the adapter to mount a carb. to a quadrajet manifold also. Thanks for any advice that you can give.
It sounds like the thermal gasket isn’t enough. Should have plenty of room under hood to run a thicker spacer. I did a video on heat soak and ways to help cure it. What you’re experiencing is common with the crappy ethanol and fuel we have today.
I'm running a hot setup on the street. It''s 468 big block Chevy with a 7,000 RPM range. According to the formula it equates to approximately 947.9 (950 cfm). As of right now I am running a 950 carburetor. Pretty much spot on. However, I'm running a FST 4500 series 950. My question, is there a big difference between 4150 style base plate, and a 4500 style base plate? The car loves the 4500 at high rpm.
Really good video on motor math . Thank you.
I ran your equation on a ZZ4 Chevy motor , 350 x5800 /3456 = 586.3 CFM carb. Chevy documents for the carb calls out for 750 CFM Holley. I have a 600 CFM double pump Holley carb. I am assuming the 750 must be jetted down and my 600 jetted up. Kinda confusing.
You cant tune CFM. It’s a fixed number. You can however adjust fuel and spark to help tune the engine to its full potential. Are you using this as a drag only engine? Any other upgrades of significance? Nitrous? Boost? Then maybe... and that’s a big maybe, a 750 would work. Only if it were a vacuum secondaries carb. Like what was mentioned at the end of the video in other details to look at to confirm the right size. What are you using the engine/car for?
No it’s not a drag vehicle, I have a 1965 El Camino . It’s just a street Rod. I have an appointment with RPM carburetor shop to get it tuned, but I watched your video and ran your numbers for curiousty. Chevy 750 carburetor was most likely for drag car. Thanks
Well a street car is a whole different story. How often do you see 5800? If you’re just cruising, not often at all. You may see it if you’re doing some more aggressive driving, but unless that’s a common occurrence, you’ll never use the CFM that carb delivers. With a 750 it’s going to be very rich pretty consistently. There are a number of other things to consider but in very general terms, it’s all about assessing how you’ll drive it and those factors that are unique to your situation.
@@MuscleCarSolutions I have a ZZ4 in a 29 model A that I just got. It has a 750 on it now but leaking and I was going to replace it. The motor has a performer RPM manifold and edelbrock mechanical fuel pump.Was told it was a stroker motor. But I'm not sure. I was wondering if you think a Edelbrock 600 or the AVS2 650 would be best? Just a cruiser hot rod. Just trying to get it running right to enjoy.
The Holley Carby maths is 99% spot on every time, be it N/A or Blown carb applications.
There's waaaayyyy too many over carbed street cars getting around with that " mystery" flat spot at WOT
Huh
I’ve seen this discussed on engine masters and the saying an engine has too much carb didn’t play out on the Westech dyno.
So put too big a carb on your car and see how it is driving around town. Dyno and real world operation are two entirely different things.
it wasnt that it was too much carb. it was more of the TYPE of carb. but i know which episode youre talking about
but they did another episode and a double pumper is obviously gonna flow more fuel. thats why they made 24 more HP vs a vac secondary of the same size. both flow 750 CFM. fuel curves are completely different. mechanical secondaries flow more on the secondary side . exactly why the double pumper is what it is, an extra shot of fuel,.
Thanks for the awesome video! I have a 289, uprated cam but nothing too aggressive in a 1931 Model A hot rod. Pretty light car, I would guess around 2200lbs and its a automatic. Currently has a 600CFM Edelbrock Performer and I’m thinking about moving to a AVS2. Its street driven with 91 pump gas. Thinking a 500CFM?
@@349a4 probably. But also need to know the cam specs so you’ll know what the engine is capable of RPM wise.
@@MuscleCarSolutionsI appreciate the reply! The car is new to me and the internals are unfortunately unknown. It has a very slightly lumpy idle and it still pulls well off idle which is all I know about the cam. My assumption is pretty mild but bigger than stock. I calculated with the assumption of 6500rpm.
@@349a4 so in this case, you can just go by how you’ll drive it. If you’re going to put it on the cams redline often, then yes use that rpm number to calculate your decision on a CFM size. If you’re not planning on driving it that aggressive, then you can use that number. If you go the second route and you have a situation where the math gives you a number in between two sizes, then go with the bigger option.
Brian, great video! I am working on my all original 1956 Ford Ranch Wagon, has the 292 V8 engine with the 3 speed manual transmission, it's a rebuild, but stock, nothing hi performance. I'm wondering which carburetor to go with, any advice? Thanks Brian!
Probably right back to the stock one would be your best choice. What did you come up with when you did the math?
@@MuscleCarSolutions 450-500 cfm The previous owner installed this cheapy 2 barrel carb., original carb was a 4 barrel, original carbs for the 292 can be costly
Hey your video are awesome,
I’m learning every time.
I just got a 1968 Chevelle with a 307 a 1406 and performer serie manifold intake is it too much?
Runs nice at high rpm if I got stuck in traffic eddy gets flooded….I think
@@dylansretreat could be too much. Really depends on the things I mentioned in this video. Tell me about the 307. Is it stock?
Hey mate, just putting together a fresh rebuilt mopar 360 with a mild cam 214/224 @.50 112 LSA. it has j heads and a dual plane air gap intake. Headers and 3:55 diff gears. Automatic transmission.
It’s a weekend Cruzer and occasional burnouts 😉.
What size cfm carb ?
Vac or mechanical?
What brand?
That’s mate. 🇦🇺
That cam is likely all done around 5800-6500? Not familiar with the flow characteristics on this heads. If it’s oe from that era they flow ok but not great. For what you’re doing, what size did the math tell you?
@@MuscleCarSolutions hey mate, yeah the cam rev range is from 2000 - 5000.
Heads are pretty stock. The calculation gave me 582cfm?
@@orlando_mopar_srt interesting. I’d expect an LSA of 112 to push way past 5500. Either way, if the cam manufacturer says 5000, then I’d stick with that. In that case I’d opt for a 600 and a 650 at the absolute most. If it’s a cruiser, you can’t go wrong with the Edelbrock. AVS2 would give you the 650cfm you need. I’m sure there’s a retailer in your country. Sounds like a fun little car. Cheers!
@@MuscleCarSolutions Thankyou for the help and reply’s mate. Much appreciated. I will stick with the 650cfm. Do you think 650 vacuum secondary or mechanical? Cheers
@@orlando_mopar_srt the Edelbrock carbs are vacuum operated secondaries. Will be just fine for what your plans are.
Hi, love the content, I've got a 383 Chrysler stroked to 489, mild hyd roller cam and alloy heads, Thinking 750cc will be enough for street, auto 4 sp and 5500 max revs ?, thanks
@@adampell1607 that’s probably where I’d start but knowing the cam specs and being honest about how you want to drive it are the some big factors.
Awesome, yep street car 99 of time. Cheers for the help👌@@MuscleCarSolutions
@ then it will be a very easy size to tune for that application. 👍
Thank you you got me headed in the right direction
Nice! You’re very welcome!
Thanks, much, Mr. ... Picked up an old stock '70 318 Dodge W200 Power Wagon, truck gears, seldom over 3000 rpm, Carter BBD 2 barrel. .. Shop manager, & local mechanic suggested a low rise/ 4 barrel Edelbrock.
Folks at Edelbrock set me up with matching manifold & #1405 600 cfm carb. ... questioned Edelbrock's service dept. about size of carburetor, & they qualified it. ... ... Just about to install. .. This video suggests I would make an incorrect/troublesome decision. .... Any knowledgeable input is welcomed.
They’re always going to go a size larger. It’s way better to be on the rich side than the lean side but in this case, if all you ever see is 3000 and below, the 500 would have been a better choice.
What’s recommended for a 1981 Chevy C10 small block 305
400 small block bored 30 over with small cam. Got a 750 cfm and a 600 cfm amdni camt seem to get either one adjusted to get the stumble out when the throttle is hammered down
Well. Start with the CFM. Which best fits your situation based on what the video showed? Next if verify initial and full timing. Then verify proper fuel system set up. Then you can start tuning.
Great video!! my application is a little different 350ci only turning 3000 MAX rpm on a airboat by your calculations a 500 cfm holly is more than enough. my question is i hear they make a 480 cfm holly 4 barrel would that be a better fit than the 500 2 barrel? Thank you in advance .
Was wondering what you think of a 750 Holly 4 barrel on a 428 cobra jet Torino, with air ram, 1969 fastback
For the same reasons in the video, I can’t answer that question without a bit more info.
I have a 84 Silverado 3/4 ton truck with a 350 motor. Truck will be used for towing/hauling and weekend driving. It had an edlebrock carb when I got the truck but I want to upgrade it. Holley 600 or 650? What do you recommend?
If towing and hauling are your plans, the Edelbrock is a better choice. Holleys works exceptionally well in WOT and racing situations.
Hi, very good explanation of how the carburetor works and how to do the math .
I’ve got a 65 Olds Cutlass with a olds 403 .060 over, headers , olds 350 heads w 65 cc cambers 9.1 :1 , Edelbrock performer rpm intake, Carter 750 , isky 262 / 262 cam , stock rear ended , HEI
TH2004r w lockup converter.
Runs so so. I did the math and it looks like a could go with a 625 or a 650 CFM Edelbrock
408cid x 5000rpm
3456 = 590.2777
Any suggestions?
Thank you for your time and efforts
Job well done.
Ernie
Kind of really depends on this one. I’d probably step up to the AVS2 and go with the 650. You’ll get some better throttle response with the annular discharge carb. Should have no trouble tuning it for that fun Olds motor. Big fan of any of the BOP engines and cars. 👍
@@MuscleCarSolutions thank you very much for your prompt reply and time . Always a pleasure to talk with someone who has been working with this kind of thing . I’d send a picture of my car but this site won’t let me .
Take care and be well
Regards Ernie
@@erniehampton5809 always happy to help!
I was using a 1.08 Autolite 4100 on my 302 in my 78 Mustang ll, I thought it ran awesome.....until i put a Summit 600 cfm on it and it woke it up. I now have aluminum heads, BluePrint HP 9008's and a much hotter cam so I'm thinking a 750 might be more in line, it will see 7k rpms at times. I looked up a 302 boss (real) engine and it show it came with a 780 Holley. Your thoughts? I am a subscriber and I have learned a lot watching your videos.
If it’s a race purpose built engine and that’s where it’s going to operate. The 750 might be a bit much, but it will ensure your top end will remain rich. Given the small cubic inches and on a race engine, I’d run a 650 HP. Give some tune ability to the mid and high range circuits.
I'm guessing the 750cfm carb on my 305 low compression el camino is slightly oversized.
It's a qjet the PO put on to replace the feedback carb it came with.
Probably way way too big.
I have a 68 f100 long bed . Has a 390 bored .040 mild cam, headers aluminum dual plane intake, and exhaust. automatic transmission. Stock gear ratio. Just a street cruiser. Probably never see 5500 rpm. What are your recommendations.
@@Mjmarquez1984 what did you come up with based on the information in the video?
It came out to a 600 cfm if I round to the nearest hundred
@@Mjmarquez1984 sounds reasonable to me if 5500 is your limit and it’s just a cruiser. Will be very easy to tune.
Great video. I’m new to this and I’m hoping you can give me some guidance. I recently bought a ‘70 c10 that has a sbc 400 with a th350 trans & a 373 rear gear. As far as I can tell the motor is stock. According to some forums I read my trans should shift at around 4500 at wot. When I do the calculations I come up with 520cfm without using the Volumetric efficiency. I’m looking at an edelbrock AVS2 carb in either 500 or 650 cfm. Would you go with the 500cfm if you were just using the truck as a cruiser for the most part?
Because of the cubic inches, I’d probably opt for the 650. Especially with that rear gear. But the biggest question would be, are you planning on any upgrades in the future? Headers, intake, better ignition, etc. if the answer is yes to any or all of them, go with the 650.
Not planning any engine upgrades. There are lots of other things that need attention. I can’t say for sure if I will do some in the future or not. That being said do you still think the 650 is the way to go? When it comes down to it I guess what I am wondering is how much the throttle response will suffer with the 650 if no changes are made to the motor.
I have a mild cam. Aluminum heads. Performer intake. Roller rockers and headers on a 351w. With that calculation it says I should be running a 500cfm 😳. Every hotrodder I’ve talked says I need to go up in cfm. I have a 600 on it now.
@@averagebogarage everyone should experience at least once how an engine runs and wears with too big a carburetor. Sounds like you’re being pushed into that lesson.
@@MuscleCarSolutions not now. Lol. One more question and thanks for ur reply. Would u go w 500 in my case or stick w the 600. It’s just a toy I drive around town and get on every now and then I’d say never anything above 4500ish rpm. Which works out to 507 using that equation. So 500 or 600. In ur opinion? Thanks again
@@averagebogarage if that’s your upper limit on RPM, both will work, but the 500 will be very easy to calibrate and have much better throttle response. Really all depends on the cam specs and how you’ll operate it. I just put a 500 on a 496 a few weeks ago into a tow rig. Flawless.
Thank you so much for the information,
I have a 400 sbc with dart iron eagle heads 2.0. ,xe 274-10 cam . I have a 750 dp quick fuel brawler.
is this too much carb? you have been a godsent to me so far. thanks 70 primary, 80 sec 6.5 power valve. has a miss when secondaried come on.
That’s a a really good cam. 230/236 on a 110. Installed a ton of them. It’s all in by 6000 though but if you’re going to the track on occasion or aggressive driving, the 750 should be just about right.
I have initial timing set at 8 and total at 35. my manifold vacuum is only showing 14 hg inches at idle of 800 rpm. msd ready to run diz with va.
I been chasing a bad stumble when you smash the throttle, bogs, spits sometimes backfires. I can ease into throttle up to 100mph but when I go wot it falls. muncie m20 4 speed. 69 Beaumont (Canadian chevelle). 3400 lbs. Could the 6.5 pv be too small or blown perhaps from all the backfiring? Appreciate any help.@@MuscleCarSolutions
@flyinhighaerial3193 couple things jump out here. 8° is not a lot of initial timing. I’m down close to sea level and start at 12-14. If you’re in Canada, I know you have some different fuel options so even if you’re running a fuel with no ethanol, add a bit more timing. Backfiring. The newer carbs have the check ball to keep the PV from being blown out every 2 minutes but it wouldn’t hurt to change it. I’d you’re seeing a stumble, you can try two things. Make sure you have the accelerator pump arm adjusted correctly and you can change the PV. If you want it to come in later and you’ve got the 6.5 in now, change it to a 5.5 and see if it gets better. Worse? Then it could be a lean condition. So go back up with the PV and try again.
Accelerator pump is adjusted. I did drive it for 5 miles to get home and it backfired plenty when I had a coil go bad a couple weeks ago. After seeing your vid on pv’s today I thought it may be the issue.
Today after warming up to operating temp I closed the choke by hand to check for a vacuum leak and could close it entirely with no change in motor. Would that indicate my pv is blown?
I’ve heard several times that Holley and Edelbrock use different vacuum ratings for their cfm ratings?
It’s an interesting question. I know they are all a little different in how they are rated from the manufacturer. What’s interesting is when they are flowed with one manufacturers process, and you put another brand on that used a different process, you’ll get a different CFM rating. Doesn’t mean it’s wrong, it just means a different set of standards was applied in the rating. I’ve thought of doing that video but I don’t have a flow bench at my disposal.
So, what I have learned for example is that a Pontiac Bonneville with a 389 means that a 700 carb ain't too much because my numbers ended up in 714 point something.
Ok so I do the tune by the main jets right now at idle the AFR is showing 14 and when I step on the gas it drops to 10 how do I the arpind rhat
Thank you for the knowledge but I wanted to ask to be sure I have a 1978 Ford F250 super cab 4x4 with a 460 4000 rpm would probably be my max rpm I'm looking for fuel efficiency more than anything daily driver if you could help me pick a cfm that would be great I run maybe 85 or 87 from the gas pump
Well, you have the key components there. What did the math tell you? Something to keep in mind here. If you really want better fuel economy, and this is something you’re driving frequently, you’ll find those big gains in the transmission, not the engine. I did a video on how to get better fuel economy in a muscle car a few years ago to illustrate how that’s possible.
@@MuscleCarSolutions sounds good I'll find the video I have a C6 automatic transmission if that helps
Love the video. Would love some input on my situation. I have an 87 suburban with a mild 454 BBC. Mild cam, long tube headers. Running a 4 speed manual and it’s also on 40 inch tires and 4.10 gears. (needs 4.56) Just a cruiser/ off-roader that I never take above 4500 rpm. But I do live in the mountains with lots of decent grades where you really need to roll into the throttle to get it to move. I ordered a Holley 570 street avenger because of the low rpms I consistently run but I’m second guessing myself because of the load it sees with the hills and grades. Any ideas would be appreciated!
Get a Performer intake, not an RPM or an air gap. Just the regular Performer, they have faster air velocity that makes more torque.
307 Small Block in a 3/4 ton manual 4 speed GMC pickup. Street drive only with a mild RV cam. Thanks for the great information.
Yup. You’ll have a much smaller CFM carb on that application for sure! Thanks for watching! Glad you found it useful!
Awesome and enlightening video! I recently purchased a '67 GTO with a 400ci and Edelbrock 600cfm, intake and a 2004R w/od trans. Runs rough and runs on. I'm now running 93 octane and I'm thinking a Holley DP 750cfm and new TV cable/throttle setup. Am I on the right track? TIA.
Don’t know. What was the size CFM you got from the information in the video? What are you using the vehicle for? Drag only? Cruiser? What have you done to address the running issues you’re having? I’d be a lot more concerned about those before I made any carburetor changes.
@@MuscleCarSolutions I’m looking at 400ci at 6000rpm w/93 octane came to a 750cfm. Definitely a cruiser. I’ve run the higher octane and even tried Seafoam but to no avail.
What’s your timing set at? Initial and all in?
When that thing was new, it probably ran great from the factory using a stock 750 CFM Quadra jet. I know gas today is not as good as it was in 1967, but the engineers at GM knew a thing or two. I would try a QJ.
Great video what whil you choose for a 1957 cadillac coupe deville whit a 365 enginge the 500avs2 or the 650 avs2 carb
Based on the information in the video, what did you come up with? If you watched it, you know that there’s not enough information given to make a recommendation.
@@MuscleCarSolutions the car is full origenal but my carb is bad en want to replace it
@@jantienesstruyk3538 understood. I still need all the info from the video. Like max rpm?
@@MuscleCarSolutions the car make max hp at 4800 rpm 320 hp thats al i now i just bouth the car ful stock only want to change the carb en go whit a electronic ignition
@@jantienesstruyk3538 ok. So now you have the CI and the RPM and you can make a choice. Seems like a pretty easy decision. The 500 would be the best way to go.
Will a 750 (CFM???) Edelbrock for my soon to be machined /rebuilt 1970 472 V8 Cadi CDV (keeping engine as OG as possible and boring only)? I've been advised to go electric choke too, so will I need press. reg, and electric fuel pump too or can I keep my og mechanical fuel pump? Thanks for awesome Vid I think my calc for CFM = 601. [472 X 4,400]/3456= 601 This car will run. 91 gas, mostly cruzin to shows and with low riders, but want to drive say within 100 miles distance on freeway 70mph. Thanks again from Sunny SD, Cali. Cholo Clem
Go with the 650 AVS2 carburetor. Better choice for what you’re doing.
Love the video I have a 462 Chevrolet with Pro race right heads elder aluminum 850 cam max rpm 6500 my spark plugs go bad very quickly. Is this carbureted working properly Is it big thank you
What does a sbc 400 come with
Hello friend, very good video I have a 2600 cc montero, doing the calculations I get 160 inch and exploring the internet I have not found a carburetor that is offroad type with so little cfm, more or less it comes out at 220 cfm rated, if you had Any suggestions I would appreciate very much
Unfortunately you’re going to be limited to what other options might have been available on those smaller engines from the factory. I’m unfamiliar with the small engine sizes but the math still works the same. Though I’m not sure the factory replacement stuff was measured in the same way. Your best bet might be finding a Mitsubishi/Toyota/Nissan type of owners group and see what they are doing for those older carbureted engines.
@@MuscleCarSolutions Thanks a lot friend, both for explaining and answering me, and for sharing your knowledge
@@lastcrew213 sorry I couldn’t be more helpful. Best of luck!
4 scenarios.
1. 70 Torino wagon 351 Cleveland 4v. auto with 3.00 gears. All is stock. It has an EB AVS 650.
2. 71 Torino GT 351 Cleveland 4v. Auto with 3.00 gears. All is stock. It has an EB 600.
3. 71 Mustang Fastback 351 Cleveland 4v. 4 speed 3.25 gears. It has headers EB Performer intake 750 Holley Dbl Pumper. MSD distributor.
4. 73 Australian Falcon 71 351 Cleveland 2v heads auto with 3.00 posi gears. It has a Holley 600 with Edelbrock Performer.
I have tri y headers to put on in the near future.
Can I use a 780 Holley or 800 EB AVS on any of these in the above configurations? Do the 4v Cleveland heads come into play? Would 4v Big heads do better with a 650 at low rpms?
Thank you.
Really you have to follow the formula in the video. Need to know your max rpm and go vehicle by vehicle and make the determination on the best size to go with.
Each would be street driven. Mostly looking for low to mid range torque. Occasionally might see 5000 rpms, but rarely
@@kennethmarston8687 so pretty easy then if you follow the basic formula in the video. If you’re staying under 5000 rpm and mostly stock engines, go with the closest number to what you came up with.
@@kennethmarston8687 I think you’ll find you’re way over carburated on some of those applications.
I got a 1971 Chevelle 402 big block 4 speed Bored over 30 on the cylinders. Trying to find the right carb for street use
Nice! What did you come up with?
First of all thank you so much for superb information regarding carburation. You have put my understanding of carburation to another level. Thanks again. I have aquestion for you thats puzzle me alot. I Have a '70 Cadillac Deville, stock engine (375 hp), stock TH400 and stock 2.94:1 rearend. Never passes, and never will, 5000 rpm. When the QJet came to age i put on a Holley 4160 600 cfm (0-80457s). I have a O2 sensor in my exhaust so i can check AFR. What puzzle me is that when passed idle i have almost perfect 14,7:1 AFR. But.... at idle, whatever i adjust or fiddle around with, it never go past 12.0:1. So my idle is a little rough and smell rich. Is there anything i am missing out when adjusting idle or do you have any idea why my AFR are so low in idle?
I run a quick fuel brawler 650 on a built amc401 took a little tuning but works great. AFR gauge is key to carb tuning
Always will get the best results with an AFR.
I have a AFR garage when you change air bleeds how many numbers to ypu change at a time.
Where can I buy air bleeds ?
@@markbogle8062 I would discourage you from making any changes to bleeds or emulsions. Those are advanced tuning strategies that are best left alone.
Yes I could use some help with my build, I’m building a 525 cubic inch motor, I’m using a Chevy big block 427 tall deck block 4.310 bore and 4.500 stroke, I bought 26cc dome pistons, use Brodix heads, either 345cc are 366cc, 119cc combustion chamber, I’m shooting for 1.7-1.8 HP per cubic inch, any help would be appreciated, thanks
Well, based on the information in the video, what did you come up with?
Since the 70’s, the math I’ve always heard was cid x 2= cfm in most street/strip applications
I suppose you could start there. Maybe those folks had different ways of thinking about it back then. For sure the parts were different. Fuel was for sure different. Less access to lots of cam grinds and cylinder heads. But like the common math problem of today, it leaves too many questions unanswered.
Doesnt really work like that. You would be putting a 900cfm on a 454.
@@cuzz63 Based on the video(s) 900+ might work, believe it or not. It's situational. 👍☺ Re-listen.
@@stuckinmygarage6220 I actually agree but its not as simple as 2x CID.
Hi. I know this is an older video but I greatly appreciate it none the less. Hope I don't overload you with info here but.... I'm less confused after watching it but still wondering which way I should go, possibly because there are so many people running over-carbed motors and I can't seem to shake that. Anyhow, I have a 66 mustang fastback with a 72' 302 and C4 3 speed Auto. It was my Dad's years ago and I managed to buy it back... cool story actually. Anyhow, I have no idea what the cam is but It definitely sounds a little more aggressive than stock. I still get 18 hg at idle from manifold when tuning so its not a crazy cam. It also has dual exhaust with long tube headers, H pipe with flowmasters (40s I think) and currently has a Holley 650 Double pumper (List 4777-3) with mechanical secondaries. Stock mechanical fuel pump. Fuel I usually run is the shell v power nitro + 91 octane (10% ethanol I believe) with a bottle of lead substitute and Orielly's octane booster. I drive pretty conservatively and only cruise it. Will never see a race on the street or strip but I might stomp on it when getting on the highway. When I run the formula, 302 x 5000 / 3456, I get 436.92 CFM. Quck Fuel makes the HR-450, a 450cfm double pumper with vacuum secondaries and Summit makes the M2008 500cfm DP with Vac. secondaries. I guess I'm ultimately asking if that's the cfm area you think would be ideal (is 450cfm enough) and if you think either of these carburetors are a good choice. OR, what would you suggest? Again sorry for the napalm of information.
So the question would be, how does the car run with the 650?
Very sluggish from the line but has plenty of top end power at 65mph highway speed. Idles rough for sure. Had the carb rebuilt and spent hours tuning it to get rid of the stumble it had on initial acceleration.
@@MuscleCarSolutionsand wow. Thx for the quick response.
@@sb328 so you tuned out that hesitation and it runs well now? If that’s the case, then what’s the trouble?
@@MuscleCarSolutionsNo, I tuned out the hesitation but it still idles rough and is sluggish. I thought maybe it was low compression but I checked all the cylinders and they're all in a good and equal range and there's no leakage from the valves if I let the gauge sit there a while, so compression is good. So I'm just thinking its over-carbed. Thought by dropping to a smaller carb I might get a smoother idle and a little more pep on the street. Just not sure how much lower I should go. My options are 450, 500, 570. Plus I'd like to keep the driver side fuel inlet as that's where I've got factory hard line running to and would be a cleaner look in my engine bay.
I have a 1986 Buick regal 3.8
Looking to buy a new carb
Any advice ? On what and where to buy ? Thank you !
Factory.
Thx for the vid!
Do you think a stock 351 Windsor 2 barrel will benefit from the "big" Autolite 2100 from a 2 barrel 390?
It's one venturi size above the stock carb.
Stock cam street driven, FMX auto.
It ist more about fiddeling around and finding the sweet spot set up for the car.
496 bbc. 6000 rpm, roller cam 250/258 @ 50.. 3500 stall. Single plane intake 373 gears. Carb recommendation, thx
So what did you come up with based on what the video taught you?
@@MuscleCarSolutions I came up with a 850, mechanical secondaries because of the cam and intake . Well.........
@@roywarren6275 I'd agree the intake can handle that, the cam can for sure and the CI of that big block sure can. How are you planning on driving it? Drag car? Street bruiser?
The car will be one weekend out of the month bruiser. 68 Camaro ladder bar set up. Like the reviews of the “QFT” carbs. Like the street Q but for better street use I like the QFT SS 850. Specs about the same for both carbs.
I think you made the right choice on the size. Sounds like a fun driver! Then again, big cubic inch big blocks are rarely boring.
Hi, I just came across your channel while watching one of uncle Tony's Garage's videos. After watching some of your videos, I was wondering if you might be able to help me sort out an issue I'm having. Here's what I have. It's a 1 ton dually with a 454, a manual transmission, 670 street avenger and 4.56 rear end gears.
The issue is a lean spot just before the secondaries open. I've tried going to a black spring which is the stiffest. It got rid of the lean spot, but I don't think the secondaries are opening.
I went one step down to the brown spring which seemed help, but there is a slight lean spot still and I can distinctly feel the secondaries open. Also with the brown spring, at times I don't get a lean spot, but I can't say for sure the secondaries are opening all the way. I don't know if the lack of a hit is misleading me compared to when I get the hit after the lean spot. All this is going wide open throttle from a slow roll at about 1200-1500 rpm. My engine has peak hp at about 4200 rpm and I don't really ever go over that.
When I go wide open throttle at say 2000 rpm and say 30 mph I can't say I ever get a lean spot.
Im not sure what other options i have.
Thanks for your video's, I've been enjoying watching them.
Which carburetor are you working with and what size?
@@MuscleCarSolutions 670 holley street avenger
@@MuscleCarSolutions it's a 670 holley street avenger. I have about 19 inches of vacuum at idle.
I’d stick with the spring that eliminates your possible lean spot. I wouldn’t worry about if they are opening or not. If they aren’t, it will fall flat on its face. It’s normal to have a smooth transition as they open and you want that! Sounds like you’ve done quite a lot to get it figured out to this point.
@@MuscleCarSolutions I haven't done a whole lot, just tried a couple springs and put a .035 squirter in from a .031, which I'm not sure was the right direction. It seemed to clean things up, but I did notice it goes really rich (10.0:1) when I lug the motor and go wide open throttle. I'm not sure if it did that before though.
I went out and drove it again, I think there is considerable amount of power difference between the black and brown spring (brown spring is lighter) It sounds different too. It also revs cleaner and faster and doesn't sound like it's struggling so much to gain rpm.
The air fuel ratio goes to a about 15.0:1 before the secondaries open all the way, it still pulls pretty good up to that point. I think im losing some power though.
Would going from a 6.5 power valve to a 7.5 maybe clean up that lean spot or am I past the opening of the PV by time i get to the lean spot. I wish incould watch the vacuum gauge at same time as the AFR gauge.
Any thoughts would be appreciated even if you still think I should stick with the heavier spring.
I’m having my 5.3ls rebuild with a mild cam heads all that good stuff. Thinking of switching to a high performance carburetor. What size should I use. I think I have a 650 double pump on it now
What did you come up with after watching the video?
Got a Ford 300 that i plan on keeping the internals mostly stock, just playing around with porting and cleaning up the factory manifolds, in your experience are the 1 barrels that came on these engines decent or should i ditch it for a smaller 2 barrel?
Boy I’ve had great luck with the 300s in the past. No kidding. I drove a cargo van from Dallas to KC with the factory one barrel zip tied onto the manifold. Somehow they vibrates loose and was stuck on the side of the road and zip ties to the rescue. Honestly unless you’re really make some big changes; cam profile, CR, you’re likely going to be ok with the factory carb. If you get into those areas, that’s when I’d look at a slightly bigger carb.
Trying to figure out carb size 78 Ford F-250 pickup , 2 wheel drive .daily driver
78 460 bored.40 over , flat top pistons, rpm dual plane intake , 3” headers, mild cam , 70 429 timing set , zf5 5 speed manual transmission , stock heads I believe..currently has a Holley 750 but considering edelbrock avs2 650 or 800cfm
Well, ignore the intake that’s mismatched to your combo and tell me what number you came up with in the equation? It’s usually very close to what size you’ll actually need.
Thanks for the response.. I’m getting 575 cfm by plugging in 468 cubic inches and max rpm of 5000 on a few different carb size calculators so my 750 is way too big .. the intake was on the motor when I purchased it and not sure the cost to replace it is worth it …. Also I’ve heard that edelbrock carbs flow less cfm than Holley of the same size .. any truth to that
73 dodge w100 360 4 speed manual. Currently a stock 1987 360. I do plan on a slightly bigger cam. Like a 340 grind. I have a 600 cfm eddy which I think is a good fit for where I want to be. It's a daily truck and I work it a bit. If I do either equation it points me to a 500 cfm carb. However with the cam in the future I think the 600 will be perfect. What do you think?
I’ll almost always plan for future use. So if the future calls for a bigger size, and you can make it work on what you’re currently running, that has always been the best option for me. No need to spend money twice if you don’t have to.
So the 600 should be a nice fit for the truck?
@@kuhndog-1196 could be. I don’t know the specs on the cam or what the rest of the set up looks like. The 360 in that truck is a fairly low rpm engine, yes? That would be the biggest factor in making the decision.
You can use a little larger cfm on a full dual plane manifold, because each side is only Drawing off one side of the carburator! :-)
Incorrect. Using a larger size will need the air speed through the venturi and booster to get the fuel flowing as the carb was designed. If you run too big a carburetor, the speed isn’t there to meter the fuel correctly. Running the correct size for the application is always best. Doesn’t matter the design of the intake.
I have a 1978 c3 corvette L-82 silver anniversary edition. I would like to upgrade the carburetor. What size cfm carb would I need and if I upgrade the air intake manifold am I able to choose any one? Ideally I would like to go fuel injected but I am not sure if I have to add an ecu or not.
Also, it is a manual transmission
@@FrankPung the trouble corvette owners universally experience is lack of under hood space. The only manifold that Edelbrock offers that will fit under that hood is the Torker and honestly, it’s not a very good intake. It is low profile however but it’s a low end power stealer. Lots of folks use them, but be prepared to lose some 2500 rpm and lower power. Yes, all aftermarket fuel injection systems have a computer to control the fuel and spark. They’re not very complicated, but you need a good installer that’s competent in that type of work or time on your own to learn how to get them set up right and how to correct any issues the system may experience.
What size carb and what type of carb would be best for a 4×4 off-road truck with a Ford 408W stroker? 6000 max rpm manual transmission 3.55 gears. The truck weight is about 5000
That’s a good one. As the mathematical answer falls at an uncommon number. So you’re using it as an off roader. You should have a cam profile and intake that is around idle-5500 rpm. If that’s true, then the off road 650 Edelbrock would be perfect.
Thanks for the content! I’m building a factory five car. The final weight is going to be about 2200lbs. I’m running a 347 sbf with a 5500 redline it’s going to be a purely street car. It’ll be mated to a tkx and irs with 3.55 gears. The math leads me to a 550 cam carb. Is that a good choice or would you recommend something else?
600 is good on a street driven car. Might step up to a 650 if you feel like that’s going to change once you get a taste for how fun it will be.
What about splitting the difference with the street demon 625?
@@Doclittle1036 that’s up to you. I hate that carburetor. 😆
Thanks for the advice. I’ll stay away from the demon
@@Doclittle1036 I did a video on the things I don’t like about it. Others have had success with them, but to me they aren’t worth the effort. It’s my bias, but I tried to give all those details in the video and the viewer can decide if it’s worth it or not.
I'm so lucky that you used the 351W as an example, since that's what I'm building! Is "Operating RPM" the same as "fast idle RPM"? Ford shop manual states fast idle RPM @ 1400. Seems very low, compared to 6,500.
Operating RPM generally refers to the zone in which the best power is made. If the set up was chosen to work together, the range is easy to determine. Most go by what the cam is rated at. It’s become a universal term of where the vehicle will be driving. Race car, high rpm. Street car, low to mid range and majority of the time.
Great video, im running a 9.8:1 383 stroker, 93 octane pump gas, auto, 3.73 and a fairly lighter car(80 malibu) the engine makes around 450-470 hp, engine builder recommended a 670 brawler( which he sells). Ivr had hell tuning this thing, i consider myself pretty knowledgeable on carbs but what size carb do you recommend. Everyone instantly says get a 750. Its a street car, but i do twist it to 6500 occasionally. Cam is 231/236 @50, 490 510 lift. Petronix ignitor iii ign, 1 5/8 longtubes, 2.02 1.6 ,aluminum heads 180cc runners, edelbrock air gap rpm intake.. I prefer vac sec for the street. Any suggestion? Im looking at Q series 750, or 750 brawler vs. What ya think?
Based on what the video taught you, what answer did you come up with?
@@MuscleCarSolutions it falls in the middle of what i have (680) and a (750), the calculation is 720cfm..
My cam specs Duration @ .050: 231*/236*
LSA: 111 + 4 ICL
@@lit549 in that instance, it’s usually the best thing for the engine to go to the bigger CFM. In this case, absolutely that’s where I’d go. 750 should be your better choice on this set up.
@@lit549 and your gurgling video is pretty common with ethanol gas. It’s boiling in the bowls. Check out my heat soak video to cure that. ;) Bonus tip. lol You have comments turned off on the video or I would have left it there.
I have a 1967 chevy 327 that is stock to mildly built I really dont any other specs....what would be a good size/brand of carb to go with?
You’re in a very difficult spot then. The only way you have left if to define how you’re going to drive it and define what your max rpm is. Then it’s a matter of living with your choice and tuning for that situation.
@@MuscleCarSolutions It's gonna be street driven, weekends and some daily driving,350 turbo trans basic little truck
Well that’s the driving part. Now make a decision on what the max rpm will be and you’re in your way to picking a CFM for that situation.