Very informative info. And yes I'm impressed with the ex side numbers . But as we have learned ( John Kasse) big flow numbers don't always mean more horse power. What I would like to see is 1 motor on the dyno and swap from one head to the other. Then we can learn even more. Port volume and valve size can make big difference in horse power numbers. You can have flow numbers from one head be greater than another but less power due to port velocity . So that why if you can get both mounted up on the same bottom end you learn a lot.
Love seeing your work, mainly because I am tired of people telling me I am lying about the heads I run on my 383. I needed a set of heads to replace a pair of cracked mexican 062s that flowed terribly anyway. I have a set of ported Assaults with 2.02 valves that flow about what your 2.08s do on a 4.030. Mine ended up about 210cc on the ports. Flow 138 @ 0.200, 192 @ 0.300, 241 @ 0.400, 274 @ 0.500, 291 @ 0.600 and 299 cfm @ 0.700. Exhaust is 107 @ 0.200, 138 @ 0.300, 164 @ 0.400, 183 @ 0.500, 193 @ 0.600, 199 @ 0.700. Exhaust port was held back by the port opening needing to fit the rectangle opening of 1 5/8" primary thorley tri-ys that use a stock L31 exhaust manifold gasket. Stayed with the 2.02/1.60 because of potential shrouding with 2.08s on a 4.030. On an 11:1 6" rod 383 with a 218/228 @ 0.050 cam on a 108 LSA installed on a 106 ICL with 1.7 rockers for 0.578 lift it moves ~430 gms/sec airflow at 5,800 rpm. Ported L31 truck intake with a plastic upper plenum ported to 80mm for a BBK 80mm throttle body. Throttle response is very snappy even with a stock diameter 4L85E torque converter that weighs every bit of 60 lbs bolted to the flexplate. ua-cam.com/video/J4v4Z9rAKio/v-deo.html
@@aidenstefanson2175 They are nice small blocks. Well unless you try to lift a head like I did and have to tear it back apart. No more JEGS parts for me.
@@chrisreynolds6520 Glad y'all figure into all this as last SBC work I did was late 80's - just simply ported iron Bowties, Manley valves on a crate 350, comp. 280 and done. Years after was only into BBC until now - building 383 from '72 Vette 350 block & rods, with Eagle crank, .060 KB hypers, Summit 1103 hyd. cam, springs, with these same DNA 153187580242 heads Eric has in video. The guide ID reads .440" and I have no idea on what valves to buy? This will be for my '91 Camaro convertible street use with MSD Atomic FI. Suggestion on what's out there appreciated.
If you buy them bare, and have Eric, Speier, or others do the potting and hard parts why not? You do realize even afr has been sourcing casting for their eliminator head from China for over a year now right? Also, maybe a history lesson, the Chinese were the first to successfully cast metals. It comes down to the quality control you are willing to pay for, pay them for quality and you will get it.
It's a cylinder heads will flow it it doesn't matter it's just a casting just because it's from China doesn't mean anything it's the hardware that's you got to replace
Still gotta be carful with the castings , though there are good ones, there are really bad ones depending on the type of aluminum they’re made from. Had a buddy , pulled out multiple rocker Studs ripped the threads right out of the head with a mid .500 lift cam.
I'm going to put my heads together and take them to a machine shop have them check them out. It's not like these are going to be everyday drivers racking up 50,000 Miles in 5 years. Most of us here are hobbist. @lollipop84858
Thanks for another great tech vid. I got some Frerra LS1 valves for my Vw heads. I had to get them cut down for my application which is only going to running 500 lift anyway. Glad I got them before prices rise. Wondering which keepers you like with Frerra LS valves? I'll be using Ti retainers :)
Watchu charge to port a set of these... Havm. Goin on a 400 w 9:1 , 2 - 36mm turbos. EFI , Victor Jr intake. TR 3650 MANUAL. Bout to get back heads from machine shop... Had steam holes n 2:08 installed.... Used only the GUD STUFF... Fresh splayed caps, billet front cap, girdle, big block snout ,internal balanced forged crank, 6" rods, pump gas sleeper..SERIOUS INQUIRY. 👍💯😎 Luv the channel
I buy these casting through Liberty Engine Parts. I feel the liberty has a little better finish work then getting them through ebay. They are wonderful for there intended purpose. I seen 562 hp on a 406 with hydraulic roller. There was a little chamber and bowl work but that was it. It was on a dyno that when ran at the track it ran like the dyno said it would. We use lots of the ford version to.
Awesome work mate. I just bought a set dart pro one 345 big block Chevy heads I'm going to put on 540 , using your advice I'm going to do light port on the heads and clean up the the chambers. Thanks from Australia !
Unfortunately it's too late but they make a set of conventional heads from MBE that you won't beat. They're not cheap they're a brodix casting where they move the cores around to reshape the port and fix the problems and it runs a rail rocker system good for 10 grand on a big block all day long and he'll Port them to size of your engine. Because there are just a complete casting that's been poured it out and completely CNC machines they're legal and conventional had classes but they fixed it problem that all aftermarket and factory big block Chevy castings have they start out tall and skinny like they should be but then they get short and wide and the damn spring pockets are right over the weakest part of the head especially the studs you start getting above 700 left you start pulling the studs out of the intake port
Similar results, roughly 3-5 cfm less , used the 2.02 valve. Havent poured yet but bet they are under 210 SF600 4.125 bore. Getting into the casting some it seems to be "foamy" in some spots. Strange.
I have a set of dart shp 220 cc heads on a 427 sbc , those castings are a lot cleaner than my shp ‘s there’s casting slashing in through the pushrod holes and under the intake ports pretty bad. is there a difference in the quality of the aluminum ??
Eric, on lower dollar standardish rebuilds, or slightly hot rodded type engine builds, where the customer isn't looking for every last horsepower, We have had really good luck with the REV & Engine Pro[Yellow & Black Boxes] Coated & Regular valves in both SBs & BBs. Actually we have been using Engine Pro stuff for a long time & the REV stuff as long as I remember! Those China heads are ok for the elcheapo guy! But they do seem to get damaged easier, when someone screws up, or is just running the death out of a nice hot rod engine! Which they weren't built for that anyway! We have seen them yank studs out on higher lift stuff & crack along the lower outer head bolt holes! Even thou they are a copy of a quality Dart head, I'm sure you felt the difference in material when you started grinding & machining! Bet it went like cutting thru soft butter 😂😂😂😂! That would be a great budget head to digitize, because there are so many companies selling basically the same part! Hope your having a good weekend & actually getting to relax a little! Remember, as a old man told me, you aren't doing anyone any good if your dead! 🤣🤣🤣🤣
Dart says they use 356 T6 on their domestic castings and they probably do. These heads probably arent 356 Al, more likely 319 alloy or some soda can material. Even the temper is questionable. It looks like a pretty good casting without too much flash. The machining looks good enough. For most guys that want a set of heads for their weekend ride they would probably work great.
How about twin plugs, one on each side of the combustion chamber? If properly set, they would be possible. Then, timing could be done to each set of plugs to tailor spark events individually for best effect.
I think its worth mentioning you have to run a spring cup of sorts or a hardened shim underneath the springs, or theyll chew the alumijum head. I also ran plus.100 valves in these heads. I also did the same with shaving them, ground the valves and seats, used milodon valves, gasket matched them and light cleanup and they work fine. Checked all the valve grind depths when i did the valve job and checked guide straightness. I also see what you did with the bronze valve guide liner after breaking through the center head bolt. I didnt hog them out, as the 2.02 is fine on the street for me. Mine were dna motoring ones. Oh and even with the plus 100 valves i still had to run offset keepers.
Don't tell my heads that the steel spring seats from Comp Cams are actually a Ford part number. They are 2" OD to match my dual springs and the ID was correct for the OD of the Assault guides. My valves are also 0.100 longer. Comparing my flow numbers to his on the intake side on a 4.030 bore, under 0.600" (my 218/228 on a 108 LSA cam has 0.578 lift on both sides with a 1.7 rocker) gave up very little with a 2.02 valve and gained a bit at 0.400 over his. My exhaust side flows less because it was ported to match a L31 exhaust manifold gasket in size and location that the flanges on my 1-5/8" primary Thorley Tri-Ys were constructed to fit exactly. Its a torque build anyway to move a heavy Express van that frequently tows a 6,000 lbs travel trailer.
@@chrisreynolds6520 Chris, have you ever tried beehive springs? How much seat pressure would you run if you were to use them on a hyd roller. Seat and at full lift?
@@getthegaff1 depends on what cam. I have run beehives. Both LS6 and Pac1218s on L31 heads. The LS6 0.550" springs once worked extremely well on milder profile cams that do not exceed 0.500" lift. I run them with Comp 787-16 retainers with the stock L31 keepers. The 1.800" installed height is reduced to about 1.750" in a L31 head. I say about because it varies a little head to head or even valve to valve on the same head. Valve face and seat wear or regrinds can alter the dimensions slightly. At 1.750" a LS6 spring should check out around 105-110 lbs and at 1.250 or 0.500" of lift from the 1.750 installed height the LS6 spring should be about 295 open pressure. The last set I tried took me buying 2-3 sets and returning the extra springs to find 16 springs that were actually within a few lbs of spec. Do not recomeend them at all now because of that, some were way out of spec. Good way to introduce a valve into a piston by causing valve float and lifter pump up at high rpm. The Pac1218s are 0.600" springs, I run those with the 787 retainers and 0.100" longer 1.6 exhaust valves. Typically requires a 0.050" spring shim to get the spring to the 1.800" install spec. On the intake valves, I use 0.050" offset locks. Stock L31 exhaust valves have shorter tips and if you run the 787 retainers and 0.050" locks, will almost certainly allow the exhaust rocker arms to slip off the exhaust valve tips. The last L31 heads I setup with Pac1218s had 0.100" longer 2.02/1.60 valves, screw-in studs, guideplates, and I ran non self aligning narrow body 1.7 rocker arms and hardened pushrods on. Added a ton of stability with the 0.554" lift and 6,500 rpm I was running.
@@getthegaff1 forgot to add, the L31 in my videos in the 1987 G20 has thick cast Speedmaster vortec heads I pulled off a L31 in a Tahoe I bought for nearly nothing with a knocking bottom end. I did a little chamber deshroud and cleanup, bowl and exhaust porting to them about 6-7 years ago. Old Blue LS6 springs before GM superceeded the number and went to a trash supplier. Comp 787-16s and stock locks. It has the pushrod holes drilled out to 1/2" to prevent the pushrods from binding at high lift with the 1.6 Scorpion self aligning rockers. Stock pressed in studs. It has a GM 94666492 roller cam giving 0.482/0.496 lift with the 1.6 rockers. Measuring with my degree wheel and a dial indicator on the lifter body, duration at the camshaft itself measured off the lifter body before the heads went on was 258/282 @ 0.006, 200/216 @ 0.050, with the stock 120K mile tight as could be L31 single roller chain set it degreed in on a 111 intake centerline and 120 exhaust centerline given it a LSA of 115.5. I left it at that despite having both a 3 way adjustable crank sprocket and a advance bushing kit layi g around. Figured 4.5* advance would be perfect for the combination. The engine has a forged L30 305 marine crank out of an engine that was frozen at 75 hours by a neighbor undergoing a nasty divorice from lack of winterization, low mileage GM LT1 Mahle flat tops from an engine that became a 396, the LT1 powdered metal rods, and a Felpro 1094 0.016" rubber embossed steel shim head gasket. It is at 10.25:1. Pulls nearly 20 in/hg vacuum at 650 rpm and revs flawlessly to 6K.
Do you have any experience with the 1st generation pro Comp Aluminum cylinder heads for a sbc ? I have a set unused. Rumor has it that they have a history of dropping valve seats? I'm scared to use them. What are your thoughts?
While we are on the subject, does anyone make cost effective AL heads for a 4.3 Chevy ? ( the one based on the 350 ) So far the ones I've seen are Brodix and big big $ . I'm really tempted to get a pair of 350 heads that have damaged cylinder 3 / 4 ) then cut and weld. 3 / 4 is the 2nd cyl from the left if the exhaust ports are facing you.
@@craigchiddo2794 Yep, I'm finding that the pre Vortec heads flowed about as much at a 305. The vid " In-Depth Build Of An Old School Chevy 4.3L V6 Build - Engine Power S9, E1&2 " on the channel " POWERNATION " for some flow numbers. The real goal is to gain the advantage of high $ porting and less weight from a pair of heads that have cyl 3 / 4 damage that is non reparable.
I have a set very similar to these and my question is at the pushrod holes the intake port has the hump going around the pushrod but it shows in the port and I'm curious if the thickness of the material cause just inside the port you can see it and was wondering if I shape that is their enough material there without cutting into the pushrod tunnel because I've busted through some pro comps before and had to weld some.thanks I tried to word is as best as I could
I am looking at picking up a set of the AFR Enforcers for a 327 build, I know you said the seats are kind of soft on these. I was wondering what you think of the quality of the actual aluminum casting?
I work at afr and ima tell you that we take almost a year to build a cylinder head. I believe our heads are down grading. We having alot of complaints. Due to not having knowledgeable workers. But good luck on your order
Can I ask why are you even mentioning .800 lift and .900 lift flow #'s? I would think for even nice race setups like .750 lift max on avg. Also the low lift #'s are seen twice where peak lift is only seen once. The diff between .030 bore and .125 bore is a like 10 cfm intake and 6 cfm exh.
Eric, do you size SBC chambers to the bore size, 4.00 or 4.125? Do any 23% SBC heads "as cast" have a chamber that's too large for a 4.00 bore? I would imagine too large a chamber that overhangs the bore creating a step would really hurting flow? It seems you can consistently get 300+ CFM out of these cheap import heads. Is this Dart copy your favorite to start with, or?
Most 23degree heads are too big for a 4.00 bore. They overhang some. It’s not as bad as you think though. I like these Chinese best of the import ones until I see the promaxx project x or the dart shp.
Eric I wanted to ask you something it seems like a lot of pros these days are moving over to a burr finish on their Port work and I was wondering is that something that you have played with? I don’t think it necessarily flows more on the bench but from what I’ve been told it makes more power I haven’t personally tested this I’m just asking
I think most “pros” are moving to it because it takes less time to do. There is very little difference in power doing it either way. I burr at the throat for atomization. I would like to burr everything to just save time but for other reasons I don’t. I might do another video on it.
@@WeingartnerRacing See that’s what I was thinking was that they’re doing it to save time and once you get good enough with your grinder control you could still do a nice job Some radius’s might have to be finished with sanding rolls but you could probably do burr finish on a lot of stuff and save a ton of time but that was really the thing I was thinking thank you for confirming that lol The major problem I see is a lot of people complaining because it gives off the image that you’re not putting in the full amount of time and lot of people aren’t used to seeing a burr finish so I’m sure you don’t want to answer questions from every single person that sees a burr finished head or intake
Check up that edel "made in USA" rpm heads for mopar la 360 mopar. Expensive and are like crap that you going to cry. I always must "renovate" that new heads. Must be China.
You saying Dart was cast off-shore is complete BS and fabrication! I talked to Dick Maskin many times....Dart was cast in North America always! Only overseas Chevy/Ford heads I would trust would come from Australia or New Zealand.
Will those heads hold a spring for a 700 life with out busting through i know they get pretty thin..... and i see the brass tubes for the head bolts do you install them
Very informative info. And yes I'm impressed with the ex side numbers . But as we have learned ( John Kasse) big flow numbers don't always mean more horse power. What I would like to see is 1 motor on the dyno and swap from one head to the other. Then we can learn even more. Port volume and valve size can make big difference in horse power numbers. You can have flow numbers from one head be greater than another but less power due to port velocity . So that why if you can get both mounted up on the same bottom end you learn a lot.
Firm believer in a good exh port as long as it isnt some gaping hole. (ie poor velocity)coupled with single pattern cams my fav
Love seeing your work, mainly because I am tired of people telling me I am lying about the heads I run on my 383. I needed a set of heads to replace a pair of cracked mexican 062s that flowed terribly anyway. I have a set of ported Assaults with 2.02 valves that flow about what your 2.08s do on a 4.030. Mine ended up about 210cc on the ports. Flow 138 @ 0.200, 192 @ 0.300, 241 @ 0.400, 274 @ 0.500, 291 @ 0.600 and 299 cfm @ 0.700. Exhaust is 107 @ 0.200, 138 @ 0.300, 164 @ 0.400, 183 @ 0.500, 193 @ 0.600, 199 @ 0.700. Exhaust port was held back by the port opening needing to fit the rectangle opening of 1 5/8" primary thorley tri-ys that use a stock L31 exhaust manifold gasket. Stayed with the 2.02/1.60 because of potential shrouding with 2.08s on a 4.030. On an 11:1 6" rod 383 with a 218/228 @ 0.050 cam on a 108 LSA installed on a 106 ICL with 1.7 rockers for 0.578 lift it moves ~430 gms/sec airflow at 5,800 rpm. Ported L31 truck intake with a plastic upper plenum ported to 80mm for a BBK 80mm throttle body. Throttle response is very snappy even with a stock diameter 4L85E torque converter that weighs every bit of 60 lbs bolted to the flexplate.
ua-cam.com/video/J4v4Z9rAKio/v-deo.html
Are you l31maxexpress on gmt400?
@@aidenstefanson2175 I am
@@chrisreynolds6520 I thought I recognized those specs! I'm vikingdude. Currently working on my own 383
@@aidenstefanson2175 They are nice small blocks. Well unless you try to lift a head like I did and have to tear it back apart. No more JEGS parts for me.
@@chrisreynolds6520 Glad y'all figure into all this as last SBC work I did was late 80's - just simply ported iron Bowties, Manley valves on a crate 350, comp. 280 and done.
Years after was only into BBC until now - building 383 from '72 Vette 350 block & rods, with Eagle crank, .060 KB hypers, Summit 1103 hyd. cam, springs, with these same DNA 153187580242 heads Eric has in video. The guide ID reads .440" and I have no idea on what valves to buy? This will be for my '91 Camaro convertible street use with MSD Atomic FI. Suggestion on what's out there appreciated.
Thank You for sharing. Excellent presentation as always!!
I feel like "using a .700 lift cam" and using "low dollar Chinese heads" should not be in the same engine
If you buy them bare, and have Eric, Speier, or others do the potting and hard parts why not? You do realize even afr has been sourcing casting for their eliminator head from China for over a year now right? Also, maybe a history lesson, the Chinese were the first to successfully cast metals. It comes down to the quality control you are willing to pay for, pay them for quality and you will get it.
It's a cylinder heads will flow it it doesn't matter it's just a casting just because it's from China doesn't mean anything it's the hardware that's you got to replace
Still gotta be carful with the castings , though there are good ones, there are really bad ones depending on the type of aluminum they’re made from. Had a buddy , pulled out multiple rocker Studs ripped the threads right out of the head with a mid .500 lift cam.
Built for a good time! Not a long time!!
I'm going to put my heads together and take them to a machine shop have them check them out. It's not like these are going to be everyday drivers racking up 50,000 Miles in 5 years. Most of us here are hobbist. @lollipop84858
Eric thanks for video and helping me God bless
Thanks for another great tech vid. I got some Frerra LS1 valves for my Vw heads. I had to get them cut down for my application which is only going to running 500 lift anyway. Glad I got them before prices rise. Wondering which keepers you like with Frerra LS valves? I'll be using Ti retainers :)
Watchu charge to port a set of these... Havm.
Goin on a 400 w 9:1 , 2 - 36mm turbos. EFI , Victor Jr intake. TR 3650 MANUAL. Bout to get back heads from machine shop... Had steam holes n 2:08 installed.... Used only the GUD STUFF... Fresh splayed caps, billet front cap, girdle, big block snout ,internal balanced forged crank, 6" rods, pump gas sleeper..SERIOUS INQUIRY. 👍💯😎 Luv the channel
I buy these casting through Liberty Engine Parts. I feel the liberty has a little better finish work then getting them through ebay. They are wonderful for there intended purpose. I seen 562 hp on a 406 with hydraulic roller. There was a little chamber and bowl work but that was it. It was on a dyno that when ran at the track it ran like the dyno said it would. We use lots of the ford version to.
Awesome work mate. I just bought a set dart pro one 345 big block Chevy heads I'm going to put on 540 , using your advice I'm going to do light port on the heads and clean up the the chambers. Thanks from Australia !
Unfortunately it's too late but they make a set of conventional heads from MBE that you won't beat. They're not cheap they're a brodix casting where they move the cores around to reshape the port and fix the problems and it runs a rail rocker system good for 10 grand on a big block all day long and he'll Port them to size of your engine. Because there are just a complete casting that's been poured it out and completely CNC machines they're legal and conventional had classes but they fixed it problem that all aftermarket and factory big block Chevy castings have they start out tall and skinny like they should be but then they get short and wide and the damn spring pockets are right over the weakest part of the head especially the studs you start getting above 700 left you start pulling the studs out of the intake port
Great work Eric! Keep the videos coming man!
What alloy are they.
Similar results, roughly 3-5 cfm less , used the 2.02 valve. Havent poured yet but bet they are under 210
SF600 4.125 bore. Getting into the casting some it seems to be "foamy" in some spots. Strange.
I have a set of dart shp 220 cc heads on a 427 sbc , those castings are a lot cleaner than my shp ‘s there’s casting slashing in through the pushrod holes and under the intake ports pretty bad. is there a difference in the quality of the aluminum ??
Eric, on lower dollar standardish rebuilds, or slightly hot rodded type engine builds, where the customer isn't looking for every last horsepower, We have had really good luck with the REV & Engine Pro[Yellow & Black Boxes] Coated & Regular valves in both SBs & BBs. Actually we have been using Engine Pro stuff for a long time & the REV stuff as long as I remember! Those China heads are ok for the elcheapo guy! But they do seem to get damaged easier, when someone screws up, or is just running the death out of a nice hot rod engine! Which they weren't built for that anyway! We have seen them yank studs out on higher lift stuff & crack along the lower outer head bolt holes! Even thou they are a copy of a quality Dart head, I'm sure you felt the difference in material when you started grinding & machining! Bet it went like cutting thru soft butter 😂😂😂😂! That would be a great budget head to digitize, because there are so many companies selling basically the same part! Hope your having a good weekend & actually getting to relax a little! Remember, as a old man told me, you aren't doing anyone any good if your dead! 🤣🤣🤣🤣
Dart says they use 356 T6 on their domestic castings and they probably do. These heads probably arent 356 Al, more likely 319 alloy or some soda can material. Even the temper is questionable. It looks like a pretty good casting without too much flash. The machining looks good enough. For most guys that want a set of heads for their weekend ride they would probably work great.
How about twin plugs, one on each side of the combustion chamber? If properly set, they would be possible. Then, timing could be done to each set of plugs to tailor spark events individually for best effect.
I think its worth mentioning you have to run a spring cup of sorts or a hardened shim underneath the springs, or theyll chew the alumijum head. I also ran plus.100 valves in these heads. I also did the same with shaving them, ground the valves and seats, used milodon valves, gasket matched them and light cleanup and they work fine. Checked all the valve grind depths when i did the valve job and checked guide straightness. I also see what you did with the bronze valve guide liner after breaking through the center head bolt. I didnt hog them out, as the 2.02 is fine on the street for me. Mine were dna motoring ones. Oh and even with the plus 100 valves i still had to run offset keepers.
Don't tell my heads that the steel spring seats from Comp Cams are actually a Ford part number. They are 2" OD to match my dual springs and the ID was correct for the OD of the Assault guides. My valves are also 0.100 longer. Comparing my flow numbers to his on the intake side on a 4.030 bore, under 0.600" (my 218/228 on a 108 LSA cam has 0.578 lift on both sides with a 1.7 rocker) gave up very little with a 2.02 valve and gained a bit at 0.400 over his. My exhaust side flows less because it was ported to match a L31 exhaust manifold gasket in size and location that the flanges on my 1-5/8" primary Thorley Tri-Ys were constructed to fit exactly. Its a torque build anyway to move a heavy Express van that frequently tows a 6,000 lbs travel trailer.
@@chrisreynolds6520 Chris, have you ever tried beehive springs? How much seat pressure would you run if you were to use them on a hyd roller. Seat and at full lift?
@@getthegaff1 depends on what cam. I have run beehives. Both LS6 and Pac1218s on L31 heads. The LS6 0.550" springs once worked extremely well on milder profile cams that do not exceed 0.500" lift. I run them with Comp 787-16 retainers with the stock L31 keepers. The 1.800" installed height is reduced to about 1.750" in a L31 head. I say about because it varies a little head to head or even valve to valve on the same head. Valve face and seat wear or regrinds can alter the dimensions slightly. At 1.750" a LS6 spring should check out around 105-110 lbs and at 1.250 or 0.500" of lift from the 1.750 installed height the LS6 spring should be about 295 open pressure. The last set I tried took me buying 2-3 sets and returning the extra springs to find 16 springs that were actually within a few lbs of spec. Do not recomeend them at all now because of that, some were way out of spec. Good way to introduce a valve into a piston by causing valve float and lifter pump up at high rpm. The Pac1218s are 0.600" springs, I run those with the 787 retainers and 0.100" longer 1.6 exhaust valves. Typically requires a 0.050" spring shim to get the spring to the 1.800" install spec. On the intake valves, I use 0.050" offset locks. Stock L31 exhaust valves have shorter tips and if you run the 787 retainers and 0.050" locks, will almost certainly allow the exhaust rocker arms to slip off the exhaust valve tips. The last L31 heads I setup with Pac1218s had 0.100" longer 2.02/1.60 valves, screw-in studs, guideplates, and I ran non self aligning narrow body 1.7 rocker arms and hardened pushrods on. Added a ton of stability with the 0.554" lift and 6,500 rpm I was running.
@@getthegaff1 forgot to add, the L31 in my videos in the 1987 G20 has thick cast Speedmaster vortec heads I pulled off a L31 in a Tahoe I bought for nearly nothing with a knocking bottom end. I did a little chamber deshroud and cleanup, bowl and exhaust porting to them about 6-7 years ago. Old Blue LS6 springs before GM superceeded the number and went to a trash supplier. Comp 787-16s and stock locks. It has the pushrod holes drilled out to 1/2" to prevent the pushrods from binding at high lift with the 1.6 Scorpion self aligning rockers. Stock pressed in studs. It has a GM 94666492 roller cam giving 0.482/0.496 lift with the 1.6 rockers. Measuring with my degree wheel and a dial indicator on the lifter body, duration at the camshaft itself measured off the lifter body before the heads went on was 258/282 @ 0.006, 200/216 @ 0.050, with the stock 120K mile tight as could be L31 single roller chain set it degreed in on a 111 intake centerline and 120 exhaust centerline given it a LSA of 115.5. I left it at that despite having both a 3 way adjustable crank sprocket and a advance bushing kit layi g around. Figured 4.5* advance would be perfect for the combination. The engine has a forged L30 305 marine crank out of an engine that was frozen at 75 hours by a neighbor undergoing a nasty divorice from lack of winterization, low mileage GM LT1 Mahle flat tops from an engine that became a 396, the LT1 powdered metal rods, and a Felpro 1094 0.016" rubber embossed steel shim head gasket. It is at 10.25:1. Pulls nearly 20 in/hg vacuum at 650 rpm and revs flawlessly to 6K.
Do you have any experience with the 1st generation pro Comp Aluminum cylinder heads for a sbc ? I have a set unused. Rumor has it that they have a history of dropping valve seats? I'm scared to use them. What are your thoughts?
While we are on the subject, does anyone make cost effective AL heads for a 4.3 Chevy ? ( the one based on the 350 ) So far the ones I've seen are Brodix and big big $ . I'm really tempted to get a pair of 350 heads that have damaged cylinder 3 / 4 ) then cut and weld. 3 / 4 is the 2nd cyl from the left if the exhaust ports are facing you.
If you did cut them that would make a really cool video I've never seen that before.
I think Edelbrock had them butThe vortec factory iron heads were almost as good and dart/ brodix they were used in lower level Nascar stuff
@@johnsheetz6639 Look up where someone cut Ford V8 heads into 2 cylinder sections then welded them together for a 300 inline 6 .
@@craigchiddo2794 Yep, I'm finding that the pre Vortec heads flowed about as much at a 305. The vid " In-Depth Build Of An Old School Chevy 4.3L V6 Build - Engine Power S9, E1&2 " on the channel " POWERNATION " for some flow numbers.
The real goal is to gain the advantage of high $ porting and less weight from a pair of heads that have cyl 3 / 4 damage that is non reparable.
I have a set very similar to these and my question is at the pushrod holes the intake port has the hump going around the pushrod but it shows in the port and I'm curious if the thickness of the material cause just inside the port you can see it and was wondering if I shape that is their enough material there without cutting into the pushrod tunnel because I've busted through some pro comps before and had to weld some.thanks I tried to word is as best as I could
What would be your choice of budget head for a sbc 406 for Sunday driver with fuel injection. Thanks
Hey Eric, with respect to a 4.03" bore, would notching the cylinder help with flow, or just use a smaller valve? Thank you.
Maybe but I don’t recommend it.
Can you cross drill a steam port into it aiming at another port or add it in some form
Thanks
I am looking at picking up a set of the AFR Enforcers for a 327 build, I know you said the seats are kind of soft on these. I was wondering what you think of the quality of the actual aluminum casting?
I work at afr and ima tell you that we take almost a year to build a cylinder head. I believe our heads are down grading. We having alot of complaints. Due to not having knowledgeable workers. But good luck on your order
what is the intake runner size after you port them? And are you going to start selling these ported?
225cc. I will most likely start advertising them.
@@WeingartnerRacing what would it cost for you to duplicate this port job on a set of these?
Can I ask why are you even mentioning .800 lift and .900 lift flow #'s? I would think for even nice race setups like .750 lift max on avg. Also the low lift #'s are seen twice where peak lift is only seen once. The diff between .030 bore and .125 bore is a like 10 cfm intake and 6 cfm exh.
Because flowing a head at higher lifts gives some indication of how stable the port will be at higher air speeds seen in the actual running engine.
What was the final Intake cc's size?!?
Hi Eric, have you had much to do with the Dart LS 10* heads, I was thinking of trying them on a 434CI LS with a supercharger
No I haven’t. It’s really expensive and most LS guys are cheap.
Y measure to 1000 lift.. wow
Are they available ?
Eric, do you size SBC chambers to the bore size, 4.00 or 4.125?
Do any 23% SBC heads "as cast" have a chamber that's too large for a 4.00 bore?
I would imagine too large a chamber that overhangs the bore creating a step would really hurting flow?
It seems you can consistently get 300+ CFM out of these cheap import heads. Is this Dart copy your favorite to start with, or?
Most 23degree heads are too big for a 4.00 bore. They overhang some. It’s not as bad as you think though. I like these Chinese best of the import ones until I see the promaxx project x or the dart shp.
Eric I wanted to ask you something it seems like a lot of pros these days are moving over to a burr finish on their Port work and I was wondering is that something that you have played with?
I don’t think it necessarily flows more on the bench but from what I’ve been told it makes more power I haven’t personally tested this I’m just asking
I think most “pros” are moving to it because it takes less time to do. There is very little difference in power doing it either way. I burr at the throat for atomization. I would like to burr everything to just save time but for other reasons I don’t. I might do another video on it.
@@WeingartnerRacing
See that’s what I was thinking was that they’re doing it to save time and once you get good enough with your grinder control you could still do a nice job Some radius’s might have to be finished with sanding rolls but you could probably do burr finish on a lot of stuff and save a ton of time but that was really the thing I was thinking thank you for confirming that lol
The major problem I see is a lot of people complaining because it gives off the image that you’re not putting in the full amount of time and lot of people aren’t used to seeing a burr finish so I’m sure you don’t want to answer questions from every single person that sees a burr finished head or intake
Where did you get them bare
KMJ
@@WeingartnerRacing cant seem to find any sbf heads from them
Glad I picked up a pair at $331 before the Jokementiaflation...
what's the deck thickness?
I never measured.
Wait.. I thought AFR was a high quality brand
They are. The purely Chinese head (with exception of valve train parts)is the enforcer line. Don’t confuse it with their cnc ported heads.
@@WeingartnerRacing ahhh.. ok...
So the valve train IS ok metals then? Interesting
Russian head is best
Check up that edel
"made in USA" rpm heads for mopar la 360 mopar.
Expensive and are like crap that you going to cry.
I always must "renovate" that new heads.
Must be China.
Nope they are cast here in Socal. Foundry is minutes from me
Waste of time flowing it over 650 , air speed rules with glide cars .
Truth is, all dart heads were always cheap Chinese heads. They just lied and said it was made in America
You saying Dart was cast off-shore is complete BS and fabrication! I talked to Dick Maskin many times....Dart was cast in North America always! Only overseas Chevy/Ford heads I would trust would come from Australia or New Zealand.
@@ericbrandt829 then which foundry did they come out of. Pretty sure foundries are illegal in USA now.
@@puunersjabski6487
You’re not very smart are you??
@@puunersjabski6487 Nope afr gmpp edelbrock cast a few blocks away from me socal
Will those heads hold a spring for a 700 life with out busting through i know they get pretty thin..... and i see the brass tubes for the head bolts do you install them
They will hold up for that lift. I install the brass tubes.