[mike 1969]

what cfm carb. should i use? i have a completely rebuilt 71 chevelle 402 with all edelbrock rpm stuff including aluminium heads & crane roller rockers & a big cam.i use it as a daily driver but take it to 5500 and above once in awhile. i have a k&n air filter on it. unfortunately this is the most recent pic i have of the engine, long before it was even started, broken in, and driven about 350 miles.

 

[stepside454]

Id use a 670 Holley personally

I see in the Pic a Holley Street Avenger...is that a 670 ? if so, Id say thats a good choice for that engine

If you stay within 5500 RPMs the 670 will be great...but if your going over it might be a little shy.
If reving to within 6000 RPMs, than Id use a 725.

 

[lluciano77]

The 670 would be a major restriction. You want a 770.

An 850 DP might be a little big. If you go DP, an 800 should be just right.

The first thing you need to do is get a different air cleaner. The one you have doen not work on Holley carbs. They sit to close to the bowl vents, causing metering problems. Sell it on Ebay and buy a good air cleaner.

 

[rifraf]

My vote is for a Barry grant speed demon vac secondary 750,I ran a 850 of the same on my 10.5 cr 292 comp cam 396 and it was too much,it ripped,but I just couldn't get it dialed perfect,I swaped it for the 750 and it is absolutely perfect.