Re: Carburetion: 2BBL vs 4BBL
Posted by:
wideblock
(75.161.4.---)
Posts: 686
Date: December 01, 2010 09:16AM
a 600 is too big for a stock 318, la or poly, as they were built for our trucks. lots of guys run them, do your homework, you'll see the 500, (actually 460) cfm is perfect for the 318 in the operating range a stock engine is designed for. from my experience, they run cleaner, stronger, and are more responsive with the 500 over a 600-650.
im stating this from memory, so pardon any minor flaws....
according to edelbrock a 600-650 is good for a 318 up to 6000rpm, but, if you read the WHOLE thing, it says to deduct 100 cfm for every 1000rpm of red-line. which puts the standard 318 (poly or la) at a 5000rpm max needing a 500-550 cfm carb. most of us will never see much over 4500rpm and that's only when we are dogging them, so a 450cfm would work perfect, unfortunately, i haven't found a 450cfm 4bbl. not to mention, even if you build a 318 that will do 6000rpm, how often will you actually wind it that high?? for most of us it would be a rare occasion that wouldn't be worth using a larger, less fuel efficient carb. i know im gonna get some argument here from the guys who have read mopar performance and hot rod mag from cover to cover, i am speaking from real world experience on a driver, not from some weekend project truck. just my 2cents