Thread: Help me choose a carb size!!

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This is my setup:

80 Camaro
350 .040 over
10:1 compr.
Ported Vortec heads w/ 1.6 rollers
Comp XE268H cam
RPM Air Gap
2400 Holeshot conver.
TH350 w/ shift kit
3.73 gears

I'm going with a Holley Avenger... just trying to decide between a 670 or 770 cfm.
This will be a street car, but not a daily driver. It will be spun to about 6500 rpm's. Thanks

Welcome to the forum!
I had a 750 Holley Vacuum secondary carb on a 350 engine that was slightly milder than yours and removed it for a 670 Street Avenger. I got the improved low speed drivability that I could never get with the 750 but I could really feel a loss when I spun the engine to it's 5500 redline. Given that background I would have to go with the 770 Avenger for an engine built like yours.

i'd lean toward the smaller carb, unless HP bragging rights or drag racing is important.

the smaller carb will have better streetability and driveablilty, with only minimal HP loss, and most of that inthe top end which you will rarely use on the street

My choice would be one of the new Edelbrock AFB carbs with the tuneable air valve...

I am currently running a 750cfm AFB on my mild 350.
Everyone said it would be too big...
I leaned it down with the strip kit and it works great.
I really do like the ability to pop the top off and switch stuff around without getting gas all over everything.
Only negative thing I can say about this carb is the strip kit. The print on the jet/rod chart is so small you need a magnifying glass to read it, and the jets and rods are stamped rather poorly and are hard to read. Other than that it is a great carb setup.
Put the electric choke kit on it too.

I had a 650 vacuum secondary Holley on it and it tried to burn the car to the ground after setting over the winter. The crossover tube o-ring got hard and it sprayed fuel all over when I started it first time in the spring... If a Holley is in the offering, I'd sure make sure it was a dual feed model.

Jeff

the predator carb is all that if skilled! lovem lovem lovem
weber 4 barrel carbs are easy to maintain an affordable. will also atomize water wash your plugs and keep your engine runnin.
600-650 cfm is desired but dont forget to tweak your carb, metering rods, jetting, fuel line, and filters all are into play and dont ever forget that air cleaners play a huge part in carb functions and performance.

My motor is built fairly similar, maybe a little more wild but i run a 750 edelbrock, had to richen it up. Great carbs, im sick of holleys, for now at least.

Clark....me personally I dont think for the street you couldnt have picked anything better than the 670Holley for your car..John

71 Nova LOL & Im the opposite..10-15 years ago I would have agreed with you, but over the last few yearsive seen alot of & heard aboutgoofy stuff with the AFBs.
While at the same time the barry Grant Demons & Holleys new street Avengers series came about....both are great carbs

You cant beat the tuning of an edelbrock or the dependability, holleys are rebuilt daily and need constant tuning, i didnt do any tuning on my carb since i had it, i tried 2 different holleys but just didnt get anywhere, Almost bought a demon til my buddy bought one and had a terrible experience with it on a brand new motor. The price of holleys is crazy, the dual feed lines, the gasket kits, the jet kits. I could rebuild a motor by the time i got done. Sure i might drop a tenth or somethin with a holley but ill stick to edelbrock til i get itchy to mess with a holley again. Stepside did you try both of these carbs? if so, any bad experiences with either???

Nova..Ive used carters ,Edelbrocks, Holleys & Rochester...I use to be partial to anything but Holley.. but lately from both personal expericance, & from friends experiances Ive found the newer Holleys to be great. John.......Merry Christmas everyone