Chevy Quadrajet Intake Manifolds

[A. G. Olphart]

In another thread, Cliff said:
"The other item that needs mentioned here are the intake manifolds.  Many of the factory intakes, even EGR versions, are excellent.  Aside from the weight, no negatives from using them, even for racing.

Right on the dyno, my slightly modded 1970 Pontiac cast iron intake, made 7 more HP than an Edelbrock RPM.  The Performer intake wouldn't even feed the 497hp engine we were testing.

At the track, I've tested the Torker, Street Dominator, Performer, and the Tomahawk intakes.  My iron intake ran .02 seconds faster than all of them.  The next best intake was the Tomahawk, with a 1" spacer.  It ran 2mph faster, but still slower in ET, showing how much low and mid-range power is lost when switching to a single plane intake."


Does this apply to Chevy casting number 6263751 as well?  This iron manifold came from a scrap yard and is likely from a pickup (carbed cars have pretty much disappeared here).  Just below the casting number is "GM3"; below and to the left of the firing order is a very large S.

Also, I'm still considering going to aluminum to reduce front end weight; what common aluminum GM or aftermarket 2 plane manifold works as well (or best ) on a small block Chevy?  

Thanks,
A. G.

[slicer87]

 I am using a GM ZZ4 intake manifold, seems to work well.

[Cliff Ruggles]

The factory small block chevy iron and aluminum intakes are excellent.  They are very well made, and the runners are sized well to compliment the small displacement engines under them......Cliff

[A. G. Olphart]

Thank you gentlemen...

I was wondering if there are a few clear standouts, as seems to be the case with square bore manifolds, and what significant differences there may be between all the factory castings.  (David Vizard shows how to improve casting 3965577 (a 1970 vintage manifold) in his carb and intake book; does my 1972 piece have shrunken smogged down runners, or is it essentially the same)?

Thanks for the tip on the ZZ4.        I am thinking dual plane for my application. 


Thanks again,
A. G.