quadrajet on RPM Air Gap with adapter

[Ed Blakeslee]

I have a zz4 engine with a Quadrajet from Cliff. I am considering a RPM Air gap manifold but will need an adapter. Do you think I might pick up some HP on the top end or will the need for the adapterbe an a regative? I have had the heads ported and added roller rockers.
Thanks fot any input
 

[Mudsport96]

It is hard to say for sure with out a dyno, but I would be willing to bet it has an affect on it. You could use a 4 hole spacer and cut and grind on it. Opening it up as much as you can, then use a grinder to blend it to the manifold opening.
I did something like that years ago. Some epoxy to seal as well as possible because of the amount of cutting I did, and blended an open center spacer to a single plane intake. By the time I was finished you would have believed it was an original quadrajet single plane.

Or you could sell it and buy a RPM quadrajet manifold.

What are your engine build specs that you need an Eddy RPM? Just a zz4 cam and ported heads? I thought the zz4 came with the GM bow tie quadrajet intake?

[quadrajam]

The adaptor will cause more trouble than its worth. As Mudsport says that Bowtie
intake is a good one.  An air gap intake is not much better than the bowtie with heat
risers blocked off. They all get hot eventually.

QJ

[Ed Blakeslee]

Thanks to all for the insight. I'll stay with what I have and try a spacer to see if it makes any difference
Ed







   

[77cruiser]

I run a 4 hole adapter on a Vic. Jr. I don't seem to have any problems. Don't drive in the cold though but if there wasn't salt on the roads from Nov. to May I might.

[novadude]

I agree that the ZZ4 intake is pretty good, and there is little to be gained per dollar spend to swap to an air-gap.  Don't know if you've ever seen this test?

https://www.motortrend.com/how-to/dual-plane-intake-manifold-comparisons/

[Mudsport96]

Stock and ported iron intake flow numbers in one picture and rpm air gap flow in the other. While I agree the rpm looks cool, some work with a grinder and you can have a stock appearance intake flow almost to just as good.