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Thread: 1976 500 head swap

  1. #1
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    1976 500 head swap

    hi im new here and was wanting to know if anybody has put 1968 472
    heads on there 1976 500 and would there be any piston to valve clearence
    problimes useing stock 76 cam for now any help would be great thanks


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  3. #2
    davesdeville's Avatar
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    Re: 1976 500 head swap

    You can use those 76cc heads on the 76 engine with no problems. You will end up with approx. 12.5:1 compression, so you'd better be using race gas. You'll have plenty of piston to valve clearance with the stock cam, and according to kwikcad500 you can use up to about a .605 lift performance cam.

  4. #3
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    Re: 1976 500 head swap

    Be prepared to break starters. You will need a really good Bat. and heavy cable too. Careful fuel line routing around the engine area helps.

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    Re: 1976 500 head swap

    cool i can live with all this only going to be a week end toy any body have a good guess to how much power and tourqe this would make and if 91 and octane booster
    would run this combo and with a 605 cam what lad would you use for the cam like
    the lumpy cams this is going in my 1964 chevy short bed has muncie m21 in it
    thanks for info herb

  6. #5
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    Re: 1976 500 head swap

    Grab the head bolts along with the heads. Some are different between the styles of heads.

  7. #6
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    Re: 1976 500 head swap

    i have the whole 1968 motor i was wondering will the muncie m21 hold up to the 500 or do i really have to use a automatic already have 4 speed conversion be a same not to use it any advice would help thanks

  8. #7
    Fleetwood472 is offline Cadillac Owners Fanatic
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    Re: 1976 500 head swap

    If you swap heads those heads onto your 76 500 thats going to put you at around 12:1 compression which I dont think you want on a daily driver because you'll have to be running it on race gas. Any set of heads from a 74 and newer 472/500 will work with your combo but not heads before 74. - Justin

  9. #8
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    Re: 1976 500 head swap

    I really don't think 91 octane plus octane booster is going to cut it for 12.5:1 iron head motor.

    As for choosing a cam I'd talk to one of the cam vendors or universal 500 parts vendors (vendors are listed at http://www.cadillacowners.com and click vendors on the left side navigation bar.)

  10. #9
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    Re: 1976 500 head swap

    well how many cc would i have to take out of these heads to reach pump gas would like to run as much compression as possible ps thanks for advice herb

  11. #10
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    Re: 1976 500 head swap

    The correct answer to your question depends on:

    Fuel system
    Timing curve and initial timing
    Engine temperature
    Air inlet temperature
    EGR system if any
    Exhaust system
    Shape of piston tops
    Combustion chamber shape
    Drivetrain, gearing, convertor stall speed if automatic
    And another dozen variables.

  12. #11
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    Re: 1976 500 head swap

    this is going in a 64 chevy stepside 4 speed no egr at least a daul 3inch exhoast flat top pistons and 411 gears already in truck what about stacking head gaskets to lower
    compression on top of ccing heads

  13. #12
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    Re: 1976 500 head swap

    Quote Originally Posted by topend1
    this is going in a 64 chevy stepside 4 speed no egr at least a daul 3inch exhoast flat top pistons and 411 gears already in truck what about stacking head gaskets to lower
    compression on top of ccing heads
    That would be an excellent custom product idea for one of the Cadillac speed parts vendors. Thick gaskets for use with small combustion chamber heads and flat top pistons. Probably need a custom valley pan gkt. too.

  14. #13
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    Re: 1976 500 head swap

    works on small block chevys but have to use longer push rods

  15. #14
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    Re: 1976 500 head swap

    anyone know what horsepower a 76 500 with 68-69 heads would be getting? a guess maybe?

  16. #15
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    Re: 1976 500 head swap

    Just guessing, going off the numbers from the Torque Pig article, I'd say a bit over 350hp and around 550ft.lbs.


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