Thread: Peanut Port Heads

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I'm going to play the low dollar hand in this game, suggesting that you don't need 500 or 600 horsepower in a lightweight street rod.

First thing to do is to cc the combustion chambers and find out what you have, then shave the heads for 115cc chambers and tailor the piston crowns so that you end up with somewhere around 9.5:1 static compression ratio.
https://www.youtube.com/watch?v=yqAr4DUqEt4

For instance, a 4.310" cylinder bore (bored +0.060" over stock)
https://www.summitracing.com/parts/uem-kb203-060
with a 4" stroke crank, 115cc chambers, 9.780" stack with a 9.800" block deck height, Mr. Gasket 1131G steel shim head gaskets (0.018" compressed) will produce a 9.53:1 static compression ratio that will operate well on pump gas without detonation, using the very tight 0.038" squish/quench outlined with the 0.020" piston deck height and 0.018" head gasket combo. You can't run the static compression ratio up too high with iron heads or you will be unable to operate the motor on pump gas without detonating it.

Use a Weiand 8122WND intake manifold to mount an 800 CFM Rochester Quadrajet and top the carb off with a 14" diameter by 4" thick air filter assembly so that the motor can breathe.

Big block Chevies will eat flat tappet cams faster than you can buy them, so plan on a hydraulic roller cam from the git-go. With this combo, I would use a Howards CL123515-10 cam and lifter kit and install the cam straight up on the numbers. Use the retainers, springs, etc. that Howards recommends for this cam.

Next would be a port clean-up and pocket port, along with a 3-angle valve job with a 30 degree back cut on the valves. You'll want a good set of full-length, tuned headers, 1.875" primaries with an "X" or "H" pipe installed immediately after the collectors, then through 2 1/2" pipes with mufflers of your choice to the rear bumper.

This modest build should produce 400 horsepower with 450 ft/lbs of torque. Using a 10", 2500 rpm stall converter, TH400 auto trans and 3.55 rear gear and limited slip arrangement should make a really nice power package for a lightweight cruiser.

If you want to step up to the plate with a VERY NICE aluminum-headed hot rod motor, follow this same game plan with a set of Airflow Research heads with 265cc intake runners and 112cc intake ports, part number 3610. You can use the same piston and static compression ratio will be 9.77:1.
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