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Thread: Peanut Port Heads

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  1. #1
    JDP is offline CHR Junior sMember Visit my Photo Gallery
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    Nov 2017

    Peanut Port Heads


    Hello Everyone,
    First time poster. Me and my son (4 years old) began building a 454 for a street rod yesterday, we picked up a dissembled 90% complete Rat motor for 150 bucks. I am hoping to at minimum make 500 HP but would much prefer 600 HP and someday in the far future add a 150 hole shot. I am planning the following:

    Performance cam
    Holly 750 (already have)
    Possible going with domed pistons to bump up the compression.

    My big question is regarding the peanut port heads that came with the motor. Is is possible to port and re-valve these heads to make that 600hp number? what about 500hp? Will those heads support a semi high lift cam?

    I ask because it would be neat to use the old heads. And would be a good cost savings anyway (doing the porting myself).

    If this wont work, can i just go find a pair of votec heads at the junkyard like I do with mouse motors?

    Sorry for the rookie question this is my first Chevy big block.


  2. #2
    jerry clayton's Avatar
    jerry clayton is offline CHR Member Visit my Photo Gallery
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    Feb 2006

    In almost any PERFORMANCE build---the redoing of older cast iron heads is more expensive than buying new alum heads with the better seats/valves/springs porting, etc already done-

    Putting 16 hardened seats, guides, oversize valves, porting, shaving surfaces for compression is going to cost you so much $$$$$$$$$ that you'll have to cancel that little guys birthday party

  3. #3
    techinspector1's Avatar
    techinspector1 is offline CHR Member Visit my Photo Gallery
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    May 2003
    Zephyrhills, Florida, USA
    Car Year, Make, Model: '32 Henway

    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.

    For instance, a 4.310" cylinder bore (bored +0.060" over stock)
    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.
    Last edited by techinspector1; 11-19-2017 at 07:52 PM.

  4. #4
    jerry clayton's Avatar
    jerry clayton is offline CHR Member Visit my Photo Gallery
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    Feb 2006

    Edelbrock has a top end package with manifold, heads, cam, timing chain plus a free carb until sometime in December--------

    Last edited by jerry clayton; 11-19-2017 at 09:15 PM.

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