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Thread: 400 heads on a 350 engine
          
   
   

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  1. #1
    Papajoe is offline Registered User Visit my Photo Gallery
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    400 heads on a 350 engine

     



    Hello everyone - My son-in-law and I built a race car, 1972 chevelle, this year and run it at our local saturday night track. We have a 350 engine with 308 heads currently and are having problems with what I believe is too much compression. We have a set of 400 heads laying around and I would like to know what to expect in the performance department if we install 400 heads on a 350 block.
    Papajoe

  2. #2
    MI2600 is offline CHR Member Visit my Photo Gallery
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    The 400 heads are probably 76cc chambers. If you're running anything smaller now, it will reduce compression by about 1.0 point.
    Don't worry about the steam holes in the 400 heads, just use a 350 gasket.
    I intend to live forever; so far, so good.

  3. #3
    Hopper111 is offline CHR Member Visit my Photo Gallery
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    I wouldn't over look those steam holes. It probably won't hurt anything if your not running the car for long periods of time but if you are, maybe you could take a little time to make those steam holes right so as not to take a chance? Or am I wrong? Are the steam holes only a problem with using a 400 block with 350 heads? Lemme Know...

  4. #4
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    techinspector1 is offline CHR Member Visit my Photo Gallery
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    "problems with what I believe is too much compression."

    What exactly does that mean?
    PLANET EARTH, INSANE ASYLUM FOR THE UNIVERSE.

  5. #5
    Papajoe is offline Registered User Visit my Photo Gallery
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    I would like to lower the compression because we have been having to use 110 fuel at $7.50 a gallon. Anything less and we have melted 3 pistons, bent 2 rods and blew 1 head gasket. Thats why I stated too much compression. Thanks to all of you for your time.
    Papajoe

  6. #6
    R Pope is offline CHR Member Visit my Photo Gallery
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    The steam holes are no problem on a 350. The 350 head gaskets are solid there. The only problem is going the other way, non-400 heads on a 400.

  7. #7
    Hopper111 is offline CHR Member Visit my Photo Gallery
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    Thanks

     



    Ok, thank you for correcting me, I couldn't remember which way the problems went but i didnt want the guy to over look them if it WOULD infact cause him problems, better to make sure than to not think about it at all.

  8. #8
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    techinspector1 is offline CHR Member Visit my Photo Gallery
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    Originally posted by Papajoe
    I would like to lower the compression because we have been having to use 110 fuel at $7.50 a gallon. Anything less and we have melted 3 pistons, bent 2 rods and blew 1 head gasket. Thats why I stated too much compression. Thanks to all of you for your time.
    Are you winnin'?
    PLANET EARTH, INSANE ASYLUM FOR THE UNIVERSE.

  9. #9
    FireBall is offline Registered User Visit my Photo Gallery
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    why would you want a 350 anyway? why not use a 400?

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