I am fighting carb selection on my GM crate motor. It will be used for street driving(alot) and also pretty much track duty. It is a ZZ4. I am running a manual transmission, headers, single plane intake and 100hp of nitrous. What do you think? Holley, Demon, Edelbrock, Carter? What size?

I'm Running 750 holley vac. secondary on zz4 w/ tremec 5 speed.

Had to decrease pri jets to 69, increase the vac spring to "brown", increase the power valve to 10.5" and increase to a 31 squirter.

it is finally dialed in now and runs great.

good luck
joe c

Hi Joe,
Have you run your car in the 1/4 mile at all? How did it run?

I believe the ZZ4 was developed using a 750 double pumper. That would be tough on gas mileage though. I used a 750 vac sec carb on my ZZ3.

Originally posted by yipman64:
Hi Joe,
Have you run your car in the 1/4 mile at all? How did it run? Haven't 1/4 yet. However, correcting for a large carb required the mentioned changes for the ZZ4 (trial and error) I'm thinking of further increasing the vac secondary spring to black, but i want to 1/4 mile it to compare any differences.
Your zz4 should pull 15 to 17" of vaccume at idle allowing for a higher than stock PV. Reduction of the jets to 69 produced great mileage and great acceleration (with help from 10.5 PV)

The car will easily run 13's, judging from performance increase over the previous 350 m-21 set up.

good luck

Pace has a "Crate Demon ZZ4" dyno tuned for the ZZ4. Mechanical secondaries, for use with manual trans.

http://www.paceparts.com/product.asp?3=55406

Your carb sounds very similar to mine with the exception of carb choice. Looks liek that would be a good way to go. What is your timign set at?

I have run 650 and 700 Demons on my ZZ4's depending on how aggressive we get with other bolt on parts (intake, nitrous, etc.). Always double pumpers and always with great success.

[ 04-29-2003, 05:07 AM: Message edited by: James67RS ]