General Category > Quadrajet Carb Talk and Tips

4988S

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Cliff Ruggles:
#48's are excellent heads, but high compression in a 400 build so plan accordingly.

Even with that said with a little work all of the Pontiac "D" port heads are pretty equal in performance potential, even the smaller valve versions.

A few  years ago we tossed a set of small valve 1969 #46 heads on a 455 build as the CNC ported aluminum KRE heads we were waiting for weren't going to be ready for the Norwalk race in August.  The customer wanted to run his car in that race so we grabbed a set of #46 heads, added screw in studs, quickly ground the small valves and seats, and put good springs on them.

We topped off the very well prepared 455 with them, and tossed in a used Crower cam from a previous build from the parts room.

Right off the trailer his car went 11.80's and ran high 11's all weekend at that race.  We were expecting maybe mid-12's out of it.........Cliff

Riv:
Thanks Cliff!  I probably won't get the heads on until the early part of next year.  First I want to see if we can figure out roughly what kind of pistons are in the engine.  Since it's running fine with the small chamber #15 heads it's possible that they're not stock.  Not sure yet.

Tim

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