400 sbc heads on 350???

Discussion in 'Engine Topic' started by david.rosol, Jul 3, 2009.

  1. david.rosol

    david.rosol Veteran Member

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    Jul 2, 2009
    Southern Maryland
    I have a question hopefully someone can help me with... Can a set of 400 heads be used on a 350? I know 350 heads can go on a 400, but must have the steam holes drilled. If I used 400 heads on a 350, do I need to do anything with the steam holes, or will the simply seal because the 350 block doesn't have them? Should I use a 350 or 400 head gasket, and would I have any extra power from doing this. I heard by putting 400 heads on a 350, it would increase mid and upper range hp. :bowtie:
     
  2. Kamikaze

    Kamikaze Veteran Member Lifetime Gold Member

    No problem! It will work but the chamber and port designs of the 400 heads weren't the best compared to others.
     
  3. pdq67

    pdq67 BANNED

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    And fwiw, some 400 SB heads are as large as 80.+ cc chamber size so I would cc them regardless.

    Try to use the earlier heavy cast heads if you can.

    pdq67
     
  4. Mwilson

    Mwilson Veteran Member

    yeah 400 heads will kill your compression
     
  5. david.rosol

    david.rosol Veteran Member

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    Jul 2, 2009
    Southern Maryland
    Thanks guys for the help... These heads are 76cc w/ 1.94 int & 1.5 ex valve sizes. I believe that's about what most 350 heads come with as well. My biggest concern was the steam holes. Thanks again.:cool:
     
  6. pdq67

    pdq67 BANNED

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    What pistons are in your engine and I hope they are 4-notch flat-tops.

    Stock type w/ +12 dish along w/ 76 heads will probably put you down around 8.5 to 1 CR is why I mention this.

    Flat-tops and 64 cc heads w/ .020" thick steel shims and a piston DITH a stock .025", right at 10 to 1.

    pdq67
     
  7. david.rosol

    david.rosol Veteran Member

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    I just checked - they are indeed pure flat top pistons w/ the 4 notches in them... Will these still make some good street power?
     
  8. cmonson

    cmonson Veteran Member Gold Member

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    what is the casting # on the heads?

    With a 350CI and the 4 notch pistons, you really should look for a 64cc head in order to run any performance based cam.
     
  9. pdq67

    pdq67 BANNED

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    Ditto!

    Then you can run any number of 268/270/272 and even a couple of 274 hy-cams so that you can begin to make some good power out of a mild street 350, imho.

    Flat-tops, 64 cc heads and .020" thick steel shim headgaskets will get you right at 10 to 1 just like stock back then.

    pdq67
     
  10. david.rosol

    david.rosol Veteran Member

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    Jul 2, 2009
    Southern Maryland
    The heads are 882 heads... I've heard both good and bad things about them, supposedly there is a light and heavy casting of the 882, and the light casting are prone to cracking - so I hear... These are supposedly the heavy casting determined by the markings... either way, I have a really good cooling system to help prevent any cracking. By the way, The engine is in my 80 Z28 w/4speed muncie and will be breathing through a set of dual 2 1/2 in flowmasters with dual hi-flow cats... no way around the cats here in NC... I'm not looking to build into a strip car - just a good cruiser with some pep if you know what I mean...
     

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