Picking the right carberator

how do i know wich one to select (cfm wise) im going with a holley duhhh but my old holley was a 750cfm and i think it was to big now that i have some what overhauled the engine i dont know if the 750 is good or maybe a 600 i just need help on knowing on how to chose the right size thanks

p.s. painted the engine pontiac metallic blue (like it was originally) and wow it looks amazing...also the parts came in today so i got about two more weeks before im tearing the streets up again..

sweet! haha hmm..im sure if you serach on yahoo theres a way to 'calculate for your carb' on how fast you want to rev the engine.. etc etc.

Bandit,

Your tag line says "built 400CI". Is that true? How much "build" has been added?

For a 406 used to drive on the street, and occasional race, a 6,000 RPM limit should be imposed. For that, a 750 Ho (AED Holley) would be the best choice. Perhaps a "Cliff-built" Q-Jet would be a good choice, as well.

For something revving higher, an 850 would be called for. A 650 is too small, regardless. Pontiacs LIKE "big gulp".

For the "nay sayers" regarding Q-Jet, Cliff Ruggles has built MANY "race" Q-Jets. One in particular is on a 462 CID Pontiac in a '69 GTO racer. It goes 9.80s ON MOTOR, with the single Q-Jet. I submit, if the carb can support that much power, "smaller" applications are easy!

Jim

http://store.summitracing.com/partdetail.asp?part=SUM%2DCEDL018S&N=0&autoview=sku

theres the setup i ordered hope it was a wise choice...im getting ants in my pants as this build comes to an end...