my friend has a 1986 Z28 IROC with a quadrajet and he is looking in to getting a new edelbrock carb and intake but what i was wondering is how many cfms is the stock quadrajet?

 

It can be made to flow 750 cfm, but I dont think most flow that well without being tinkered with.

 

GM produced millions of Q-jets. There are many different sizes and variations. The Q-jet has more tunability than a Holley does but you need to know what to do.

I believe most of the SBC Q-jets were around 625 CFM. There might be some small 500 CFM versions floating around and some 800 or 825 CFM BBC Q-jets. Without looking at part numbers you can't tell what size it is just by looking at it.

 

He should keep the Qjet. It is an EXCELLENT carb with great tuneability. And when the secondaries come online, watch out!

Go to www.thirdgen.org and look in their Tech Articles for the ones on the QJet. That shows you how to tune the things within an inch of their lives--and they HOLD a tune for years, too

 

he wants me to think of a setup for his car and i thought i would go with 650cfm edelbrock carb and a edelbrock performer air gap manifold

 

That'd be pretty good for an '86 305 IROC.
Most Q-jets were 750cfm, with an occasional 800cfm in late '79-81 noted by their "Bumps" in the primary veturi.