65stang4me

Helping my father in law build a stroked 302. Going to purchase a new carb for him as a late fathers day and birthday gift. We plan to stroke the engine to 331, go with a streetable hydaulic roller cam, aluminum heads, etc. I was planning to purchase a Edelbrock carb, but they offer a 600 cfm which seems like it might be too small and a 750 which could be too big???? I've never been a big Holley fan so I'd rather not go that direction. Is a 750 too big or could we adjust it to work well with a smaller displacement engine?

2+2GT

600 should be plenty unless you are racing, as in trailering to the track on weekends and occasionally blowing up the engine racing.

Try this:

http://www.4secondsflat.com/Carb_CFM_Calculator.html

JMD

I would say a 600 will be plenty of carb for that build.

Norm Peterson

600 will be plenty.

At 95% volumetric efficiency (higher than what you'll end up with), 600 cfm will support 331 cubic inches at 6600 rpm - and if you're going to be operating above that rpm you should probably be looking at a solid roller cam. Anyway, a 600 would be providing 1.5" Hg restriction (about 0.75 psi) at that point.

A 750 cfm would provide slightly less restriction at that rpm (about 0.5 psi). All else equal, that's worth less than 2% power at that rpm. At more normal rpm's it won't even be worth 1%.

I think that Chevy used to use a Holley 585 cfm on engines at least as large as the 327.


Norm

kalli

in case noone mentioned it before .... 600 is plenty ;-)
had a 570cfm holley on a 300HP 302, no lack in power up top (6000+)