You are absolutely correct regarding the older or conventional 4160s; in the past you would have used spring rating and the metering plate to tune the secondary side. Now, as many of you know Holley has seen the wisdom of incorporating metering blocks and thus removable jets in the secondary side of many newer or revised 4160s. Stay “tuned”.
Thank you summit for your videos, this is why I choose to spend my money with you. Tech support is the best in the business. Thanks for the summit carb I love it. You guys are the king of hot rods!
Hi Dave, A properly sized and tuned carburetor should totally alleviate the sacrifice you are hinting at. I have not discussed this formula yet but always size the carburetor correctly for cubic inches, RPM, volumetric efficiency and of course application. I would qualify the following formula by stating that this is based upon 1) a naturally aspirated application and 2) 100% volumetric efficiency. Size in CFM = Displacement in cubic inches x Maximum RPM / the constant 3456. Stay in touch.
Its actually a 780, the secondary venturis are bigger, measure them if you dont believe me ! Dont feel bad, lots of people make that mistake ! That is why the holley book shows a bigger jet size in them than the 750 .
Hi Damian, You know I went back and watched the video several times and sure enough I didn’t even mention secondary metering plates - Yikes! So, let me say that Holley does offer secondary metering plates and they are one of the methods of tuning the back half of an older or conventional 4160. The plates themselves use drilled restrictions for the secondary idle feed restriction and the secondary main metering restriction instead of removable jets.
Good catch Damien, and you’re right. I’ve watched the video several times now and I completely forgot to mention the secondary metering plates. Believe me I’m sorry I forgot them, they are important and they are MIA in this video - sorry. I have incorporated some additional information about the plates in my reply to Damian elsewhere in this thread. I hope to incorporate them elsewhere in this Holley 4150/4160 series of videos. Thanks for watching.
Hi, thanks for your videos. I have a question. I own a Chevrolet Silverado whith the 7.4l 454 bored over 0.50 whit bigger cam, automatic transmission. What tipe of carburetor would you recommend me to use?
hello my question is: I have a 750 vacuum ,motor is 327, .020over 10,50 30-30 cam 194's heads any vacuum 2nd have adjustable idle mixture give any more air on idle? mostly brackets little street..
I just bought a reman'd 4010 750cfm spread bore with mechanical secondaries for my olds 455, its got a high profile cam, .060 over bored, and some other small odds and ends don. its one of the discontinued models, but im still confused about how to tune the secondaries, the guy said its very similar to the primaries, but since the secondaries will obviously guzzle more gas, should I raise the float level up about 1/2 to 3/4 above recommended levels or adjust according to instructions
I have a 600cfm 2 barrel country quick fuel. Having trouble with pull over through squirter in above idle, mid and upper throttle positions. Any tips to stop squirter pullover
Hi Chase Reynolds, A good diagnostic tool is a fuel pressure gauge mounted where it can be monitored while driving. If at wide open throttle you see a 3-4 pound drop in fuel pressure going into the carburetor, this is an indicator that the fuel pump is having a difficult time keeping up! Another thing is the tune up. Has the cap, rotor and plug wires been replaced recently. These are a few easy checks that go a long way to properly diagnosing a problem!
If I’m still getting that sag you talk about from primaries to secondaries with a black spring I then need to look at float level, then secondary jetting???
My secondary venturies on a street avenger are not injecting any fuel at all into the intake, I know for sure that the fuel level is all good and set on the secondary chamber... what am I missing?
Hi Ricardo, Can you tell us a list number? Also, when is this occurring-at idle, during cruise, when I throttle it/floor it? Have you tried the paper clip trick?
Summit Racing yes, already “fixed” it by removing the secondary vaccum spring, it was too rigid... are there risks of running with no spring? Seems ok, because the secondaries close just fine due to the linkage in the throttle... but I dont know what could happen
Is it okay to run a Holley with vacuum secondaries on a supercharger? Recently got a car that came with a Weiand 142 on a 350, the prev owner put a Street Avenger 670 on it. Has a 700R4 auto trans. I've verified that the secondaries are opening using a metal clip on the secondary vacuum actuator rod.
hey mate. i have valiant charger with 360 small block. i have a 750 vac secondary with quickchange housing. i can feel the secondarirs come on. am i experiencing a flat spot untill then or just getting a a hit from the secondaries. cause i was sure that you shouldnt feel them.
001ains what spring are you using? Also make sure your fuel level in the rear bowl is higher so it is easier to pull fuel over. It usually is leaning out on transition.
+Summit Racing please do videos on your own Summit Racing Carbs, instead of Holley's. People say they're pretty much the same but the design is different and I understand the concept is pretty much the same but, I'd like to see just Summit carbs. I'm having trouble with my secondary overfilling and I've cleaned and adjusted the needle for the float to seat at a lower setting. Wish I would've went with a Holley instead of Summit. I'm ready to throw this carb away and take the loss on carb. I've replaced the FPR and gauge, adjusted the pressure and still to no avail, same issue. Your guys Summit carb is costing me more money, with replacing plugs, oil and oil filter because of overloading.
+Summit Racing I'm running your M2008 series carb with your G3136-2 fuel pump that hurts my ears and my Mustangs feelings because it's louder than my motor. lol I love Summit parts but, I'm ready to just junk it all and buy all Holley parts through Holley. They'll guarantee their parts as I'm sure that Summit will as well.
You are absolutely correct regarding the older or conventional 4160s; in the past you would have used spring rating and the metering plate to tune the secondary side. Now, as many of you know Holley has seen the wisdom of incorporating metering blocks and thus removable jets in the secondary side of many newer or revised 4160s. Stay “tuned”.
Thank you summit for your videos, this is why I choose to spend my money with you. Tech support is the best in the business. Thanks for the summit carb I love it. You guys are the king of hot rods!
Hi Dave,
A properly sized and tuned carburetor should totally alleviate the sacrifice you are hinting at. I have not discussed this formula yet but always size the carburetor correctly for cubic inches, RPM, volumetric efficiency and of course application.
I would qualify the following formula by stating that this is based upon 1) a naturally aspirated application and 2) 100% volumetric efficiency. Size in CFM = Displacement in cubic inches x Maximum RPM / the constant 3456. Stay in touch.
Holley made a 950 secondary vacume operated 3barrel.. Thing is a beast. Runs so much better than my 4150 double pumper.
Its actually a 780, the secondary venturis are bigger, measure them if you dont believe me ! Dont feel bad, lots of people make that mistake ! That is why the holley book shows a bigger jet size in them than the 750 .
another good carb video by summit!
Hi Damian,
You know I went back and watched the video several times and sure enough I didn’t even mention secondary metering plates - Yikes! So, let me say that Holley does offer secondary metering plates and they are one of the methods of tuning the back half of an older or conventional 4160. The plates themselves use drilled restrictions for the secondary idle feed restriction and the secondary main metering restriction instead of removable jets.
Good catch Damien, and you’re right.
I’ve watched the video several times now and I completely forgot to mention the secondary metering plates. Believe me I’m sorry I forgot them, they are important and they are MIA in this video - sorry. I have incorporated some additional information about the plates in my reply to Damian elsewhere in this thread. I hope to incorporate them elsewhere in this Holley 4150/4160 series of videos. Thanks for watching.
Thank you for watching, boostinbo!
zoom in to the carb more often. cannot see operation
Do I need to retain the equalizer tube on my 71 383 road runner Holley, thanks
Vacuum Sec. have Metering Plates instead of Metering Blocks.
Hello would love help choosing correct carb
Tuning secondary side with 50 cc pump. The lever seems to be pushing half way down at closed throttle so at .015 at WOT I'm only getting half shot?
Get the pump cam set up correctly.
Norm rules!!!
Thank you for watching!
Hi, thanks for your videos. I have a question. I own a Chevrolet Silverado whith the 7.4l 454 bored over 0.50 whit bigger cam, automatic transmission. What tipe of carburetor would you recommend me to use?
hello my question is: I have a 750 vacuum ,motor is 327, .020over 10,50 30-30 cam 194's heads any vacuum 2nd have adjustable idle mixture give any more air on idle? mostly brackets little street..
What about low vacuum cams
I just bought a reman'd 4010 750cfm spread bore with mechanical secondaries for my olds 455, its got a high profile cam, .060 over bored, and some other small odds and ends don. its one of the discontinued models, but im still confused about how to tune the secondaries, the guy said its very similar to the primaries, but since the secondaries will obviously guzzle more gas, should I raise the float level up about 1/2 to 3/4 above recommended levels or adjust according to instructions
I have a 600cfm 2 barrel country quick fuel. Having trouble with pull over through squirter in above idle, mid and upper throttle positions. Any tips to stop squirter pullover
can I change the jets in the secondary block to bigger numbers in a 4150 holley?
Hi Steliosz28,
Yes, 4150 carbs have a secondary metering block with interchangeable jets!
Summit Racing Hi I have a 4150 with secondary jets a 80 and 90 does it matter in which order they are mounted?
im getting a stubble or cutting out at wide open throttle could the secondaries not be opening and not praying fuel
Hi Chase Reynolds,
A good diagnostic tool is a fuel pressure gauge mounted where it can be monitored while driving. If at wide open throttle you see a 3-4 pound drop in fuel pressure going into the carburetor, this is an indicator that the fuel pump is having a difficult time keeping up! Another thing is the tune up. Has the cap, rotor and plug wires been replaced recently. These are a few easy checks that go a long way to properly diagnosing a problem!
Buy a better razor.
If I’m still getting that sag you talk about from primaries to secondaries with a black spring I then need to look at float level, then secondary jetting???
Please stop saying puppy like that.
Also these are great videos thank you.
Yeh if its a 4160, he didnt talk about metering plates at all.
Yes u missed
As everyone else small needle tune for
SecondAries
Manual transmission!!?? Ever been to a race track? Or a fast street car
If my motor runs good with 68 mains where should I start with my secondary jets?
My secondary venturies on a street avenger are not injecting any fuel at all into the intake, I know for sure that the fuel level is all good and set on the secondary chamber... what am I missing?
Hi Ricardo, Can you tell us a list number? Also, when is this occurring-at idle, during cruise, when I throttle it/floor it? Have you tried the paper clip trick?
Summit Racing yes, already “fixed” it by removing the secondary vaccum spring, it was too rigid... are there risks of running with no spring? Seems ok, because the secondaries close just fine due to the linkage in the throttle... but I dont know what could happen
Is it okay to run a Holley with vacuum secondaries on a supercharger? Recently got a car that came with a Weiand 142 on a 350, the prev owner put a Street Avenger 670 on it. Has a 700R4 auto trans. I've verified that the secondaries are opening using a metal clip on the secondary vacuum actuator rod.
Yes, you can run a vacuum secondary carburetor with a roots-style supercharger with no problems.
@@SummitRacing Thanks!
hey mate. i have valiant charger with 360 small block. i have a 750 vac secondary with quickchange housing. i can feel the secondarirs come on. am i experiencing a flat spot untill then or just getting a a hit from the secondaries. cause i was sure that you shouldnt feel them.
001ains what spring are you using? Also make sure your fuel level in the rear bowl is higher so it is easier to pull fuel over. It usually is leaning out on transition.
where is the vacuum secondaries check valve located? I'm working on a750 and is giving me a fit. i rebuilt a750 double pumper no problem in the past.
+Michelle Stancil,
That check ball is actually located in the housing of the secondary diaphragm. Thanks for watching!
+Summit Racing please do videos on your own Summit Racing Carbs, instead of Holley's. People say they're pretty much the same but the design is different and I understand the concept is pretty much the same but, I'd like to see just Summit carbs. I'm having trouble with my secondary overfilling and I've cleaned and adjusted the needle for the float to seat at a lower setting. Wish I would've went with a Holley instead of Summit. I'm ready to throw this carb away and take the loss on carb. I've replaced the FPR and gauge, adjusted the pressure and still to no avail, same issue. Your guys Summit carb is costing me more money, with replacing plugs, oil and oil filter because of overloading.
+Summit Racing I'm running your M2008 series carb with your G3136-2 fuel pump that hurts my ears and my Mustangs feelings because it's louder than my motor. lol I love Summit parts but, I'm ready to just junk it all and buy all Holley parts through Holley. They'll guarantee their parts as I'm sure that Summit will as well.
Secondary metering plates?
Hey, what' cam do I need on 750 hp 4150 on secondary.
Norm have you seen those adjustable covers from QUICK FUEL?
Do you still use a spring with those?
YES