Need a little help here.Im buildin a 350 im usin a cam with a 224 duration and a470 lift rpm range 1500-6000 hedman header reman recon 350 for a 79 camaro.What i need to know what would be a good manifold i was think in edelbrock RPM performer or th Air Gap performer which one of these are better.Form what i read there pretty close

 

Also 2400 stall converter and 373 gears.........

 

for the price why not go with the air gap. I have heard good results from them especially when iced down. Sounds like a nice combo you got.

 

If you can get a performer rpm for less than 100 I would go for it. I called ebrock shortly after the airgap came out and they said if I had already modified my divider (which I had) and was using a spacer then the hp difference was less than 10.

You can also find some airgap clones on ebay for about 140.

actually, both intakes are the same height. 4.65 inch at carb base.

 

As a general rule for performance you can feel, the bigger is better. If you can fit the air gap under your hood then go for it.
SSC

 

i dont think there would be a noticble differance between the RPM and the Air Gap RPM. the manifolds internal dimetions are identicle, and u can block off the exhust cross over with differnt gaskets. Also the Air Gap cost more. so if u ask me, i would recomend the regular RPM

 

Longer the intake runners, lower the horsepower, more torque. Bigger the plenum width, higher the power is upand more, lower torque. Sounds like it should be reversed, but thats the way it goes. Edelbrock will specify things for your needs.

Also saw that they just introduced the EXP or something manifold which is the evolution of the RPM manifolds; 9 hp more and 10 lb/ft with no shift in the power band, looks really cool!

I dont know how far you are, but you should match you cam to you intake and heads, not the other way around. But it can be done, not as well though.

 

If you do any winter driving at all, you'll appreciate the internal
plenum heating of the regular performer rpm over the airgap.
Also the fully divided plenum will have more bottom end torque and throttle response and cruise nicer. The air gap would show
a slight power advantage at the drag strip if cooled between runs and slightly more top end hp at the expense of low end torque and throttle response, with its semi open plenum.

 

Well to post another on this subject.
I use an Excellerator single plain on the street for my 76 Pu. No bottem end difference more top end rpm, also the anoying sucking sound common with open element air cleaners is gone. But there is no low rpm loss over the stealth. Weiand makes far superoir manifolds than edelbrock so why not just get a stealth???
SSC