ZZ4 Carburetor
Thread Starter
Melting Slicks
Joined: Jun 2005
Posts: 2,239
Likes: 74
From: Palatine, Peoples Republic of Illinois
St. Jude Donor '09-'10-'11-12-'13-'14-'15-'16-'17-‘18
NCM Sinkhole Donor
ZZ4 Carburetor
I have a ZZ4 in my '70 with headers and a TKO 500 trans and a 3.36 rear gear. I have an Edelbrock 1406 600 CFM carb on it now and am thinking or swapping it out for a Holley 770 that Jegs has listed for a ZZ4. Does anyone have experience with this carb? It's listed as GM Performance number 19212046 if that helps.
Thanks,
Jim
Thanks,
Jim
Race Director
Joined: May 2006
Posts: 18,737
Likes: 2,583
here's a test of the ZZ4 including that carburetor
http://www.hotrod.com/how-to/engine/...hevy-bolt-ons/
http://www.hotrod.com/how-to/engine/...hevy-bolt-ons/
Melting Slicks
Joined: Dec 1999
Posts: 2,116
Likes: 156
From: Mid West
Cruise-In III Veteran
A 770 cfm carburetor is unnecessarily large for a 350" engine and unless it has vacuum secondaries it'll cause a big bog when used with an automatic transmission and a full throttle start. A 350" engine that is running with a 100% volumetric efficiency can only swallow 608 cfm at 6000 rpm so any carburetor that flows more than that is overkill. Street engines with automatic transmissions need vacuum or AVS type carburetors.
I have a ZZ4 in my '70 with headers and a TKO 500 trans and a 3.36 rear gear. I have an Edelbrock 1406 600 CFM carb on it now and am thinking or swapping it out for a Holley 770 that Jegs has listed for a ZZ4. Does anyone have experience with this carb? It's listed as GM Performance number 19212046 if that helps.
Thanks,
Jim
Thanks,
Jim
Melting Slicks
Joined: Jun 2011
Posts: 3,116
Likes: 598
I have a ZZ4 in my '70 with headers and a TKO 500 trans and a 3.36 rear gear. I have an Edelbrock 1406 600 CFM carb on it now and am thinking or swapping it out for a Holley 770 that Jegs has listed for a ZZ4. Does anyone have experience with this carb? It's listed as GM Performance number 19212046 if that helps.
Thanks,
Jim
Thanks,
Jim
https://www.holley.com/products/fuel.../parts/0-80770
I found this to be a very picky carb. A lot of adjustments, from Power Valve, Vacuum Secondary Springs, Jets , accelerator pump Cam's etc. When you get a carb with this CFM size you need to make sure you don't have any vacuum leaks. I found this out chasing bogs on quick acceleration for weeks. I almost gave up. The smallest leaks caused low RPM bog problems. I also had the advantage of using my AFR data logger to help me see what is happening.
Do you have any baseline 1/4 mile speed or HP measurements so you can do a before and after.
Hopfully the change you are looking for can be measured. Are you looking for 1/4 mile speed; extra power ???
I am assuming you are not happy with the current performance.
Thread Starter
Melting Slicks
Joined: Jun 2005
Posts: 2,239
Likes: 74
From: Palatine, Peoples Republic of Illinois
St. Jude Donor '09-'10-'11-12-'13-'14-'15-'16-'17-‘18
NCM Sinkhole Donor
Looks very similar to this
https://www.holley.com/products/fuel.../parts/0-80770
I found this to be a very picky carb. A lot of adjustments, from Power Valve, Vacuum Secondary Springs, Jets , accelerator pump Cam's etc. When you get a carb with this CFM size you need to make sure you don't have any vacuum leaks. I found this out chasing bogs on quick acceleration for weeks. I almost gave up. The smallest leaks caused low RPM bog problems. I also had the advantage of using my AFR data logger to help me see what is happening.
Do you have any baseline 1/4 mile speed or HP measurements so you can do a before and after.
Hopfully the change you are looking for can be measured. Are you looking for 1/4 mile speed; extra power ???
I am assuming you are not happy with the current performance.
https://www.holley.com/products/fuel.../parts/0-80770
I found this to be a very picky carb. A lot of adjustments, from Power Valve, Vacuum Secondary Springs, Jets , accelerator pump Cam's etc. When you get a carb with this CFM size you need to make sure you don't have any vacuum leaks. I found this out chasing bogs on quick acceleration for weeks. I almost gave up. The smallest leaks caused low RPM bog problems. I also had the advantage of using my AFR data logger to help me see what is happening.
Do you have any baseline 1/4 mile speed or HP measurements so you can do a before and after.
Hopfully the change you are looking for can be measured. Are you looking for 1/4 mile speed; extra power ???
I am assuming you are not happy with the current performance.
Melting Slicks
Joined: Jun 2006
Posts: 2,071
Likes: 147
From: S Nevada
Although I have a much larger edelbrock avs carb on my modified 383, I had to tune the carb. No matter what the carb manufacturer would like you to believe about out of the box ready to run.
In your case, if the carb is running well other than wot stumble, simply moving the pump link drive to a hole close to the carb body will increase the plunger stroke length, resulting in more fuel delivered.
I bought the jet kit. I had to go 2 stages leaner in the primary circuit and 1 stage leaner in the secondary circuit. The carb seems to perform very well.
The pump link change is free, a jet kit about $65. Either way, cheaper than another carb.
In your case, if the carb is running well other than wot stumble, simply moving the pump link drive to a hole close to the carb body will increase the plunger stroke length, resulting in more fuel delivered.
I bought the jet kit. I had to go 2 stages leaner in the primary circuit and 1 stage leaner in the secondary circuit. The carb seems to perform very well.
The pump link change is free, a jet kit about $65. Either way, cheaper than another carb.
Melting Slicks
Joined: Dec 1999
Posts: 2,116
Likes: 156
From: Mid West
Cruise-In III Veteran
For what its worth, I use to run that exact carb on my ZZ4 years ago when it was unmodified. Even with adjusting the accelerator pump linkage and tuning the jets, rods, and springs I never could get the engine to respond well with that particular carb. I think Edelbrocks are great, but I never could get it tuned well on my ZZ4. Either I had low speed running (idle and cruise) dialed in with poor WOT, or vise versa. Never did figure out why that was, but eventually I ended up going the Holley type of carb. route.
Good luck,
Jason
Thread Starter
Melting Slicks
Joined: Jun 2005
Posts: 2,239
Likes: 74
From: Palatine, Peoples Republic of Illinois
St. Jude Donor '09-'10-'11-12-'13-'14-'15-'16-'17-‘18
NCM Sinkhole Donor
Thanks. I'll try the pump linkage first but if that doesn't work I think it's new carb time.
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Melting Slicks
Joined: Dec 1999
Posts: 2,116
Likes: 156
From: Mid West
Cruise-In III Veteran
Thread Starter
Melting Slicks
Joined: Jun 2005
Posts: 2,239
Likes: 74
From: Palatine, Peoples Republic of Illinois
St. Jude Donor '09-'10-'11-12-'13-'14-'15-'16-'17-‘18
NCM Sinkhole Donor
Decided to go with the Holley 770 and all I can say is DAMN! Had a few issues with the setup but once I got all the leaks plugged and the metal shavings out of the needle valve it really woke the engine up! Driving the car now is like an amusement park ride.
Melting Slicks
Joined: Jan 2012
Posts: 3,039
Likes: 504
From: myrtle beach sc
Army
I had bought a Holly 670 street avenger carb for my ZZ4 and I tried to get the bog out of it, when you floored it.
After trying all kinds of things, I finally gave up and bought a Holly spread bore. I had used one on my L-79 for over twenty five years and loved it.
The spread bore worked great right out of the box. You guys can keep the tinkering on your regular Holly carbs. Lou.
After trying all kinds of things, I finally gave up and bought a Holly spread bore. I had used one on my L-79 for over twenty five years and loved it.
The spread bore worked great right out of the box. You guys can keep the tinkering on your regular Holly carbs. Lou.
Last edited by loup68; Jul 24, 2015 at 08:08 PM.
Thread Starter
Melting Slicks
Joined: Jun 2005
Posts: 2,239
Likes: 74
From: Palatine, Peoples Republic of Illinois
St. Jude Donor '09-'10-'11-12-'13-'14-'15-'16-'17-‘18
NCM Sinkhole Donor
I had a bad bog with the Edelbrock 1406 but none with the Holley. Did you have vacuum secondaries or mechanical?
Melting Slicks
Joined: Dec 1999
Posts: 2,116
Likes: 156
From: Mid West
Cruise-In III Veteran
Glad things worked out for you.