Head gaskets and quench.

Discussion in 'High Performance Modifications' started by Farmtruck53, Sep 16, 2020.

  1. Farmtruck53

    Farmtruck53 Member

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    Good afternoon to all. I need some information on which head gaskets and Quincy for my sb. I am installing 64cc promaxx aluminum heads on a 355 with summit hyper pistons that are 1.56 compression height. Stock deck and my best measurement is 0.25 in the hole. Stock. I have a 1094 0.15 gasket which should give 40 quench. I also have a victor 0.26 grafite that would give a 0.51 quench. Which would you use and why? Can't decide. Help appreciated.
     
  2. Farmtruck53

    Farmtruck53 Member

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  3. Farmtruck53

    Farmtruck53 Member

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    Quench. Sorry spell Ck got me
     
  4. 1980RS

    1980RS Veteran Member

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    I would use the thinnest gasket you can find for aluminum heads as the tighter the quench the lees detonation there will be.
     
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  5. Farmtruck53

    Farmtruck53 Member

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    Thanks. That's what I've been reading but just wasn't sure if alittle less quench was ok. The Victor gaskets I have been told would seal better.
     
  6. 70lt1z28

    70lt1z28 Veteran Member Gold Member

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  7. G72Zed

    G72Zed Veteran Member

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    X2^^ Same goes for Iron head application, If I can get the part number on the piston top to "ghost" on the head, then I'm good LOL.
     
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  8. jeff swisher

    jeff swisher Veteran Member

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    I did just about the same thing.
    I had my flat top pistons .013" down the hole and ran .015" gasket I had 54cc chambers 350"
    .028" total piston to head.
    Ran awesome.
    Later I went with a thick gasket and got .051 piston to head and the car ran the same Only difference was very hot days 90+ outside temps I had to pull 2 degrees of timing from the tight quench deal.
    The larger piston to head was not as finicky.
    .051-.053" may be the cut off.
    I am currently running .051 with different heads and cams and it is not detonation sensitive.
    22 initial 38 total 35 total is down 3 HP.
    This is a cast piston and Iron heads.
     
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  9. Farmtruck53

    Farmtruck53 Member

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    Thanks Jeff. That's exactly what I was looking for. Somebody that had actually done it. I had a sealing issue with the shim gaskets I had. Smoked alittle from the right bank when cold. Could never figure it out. Thought maybe valve guide or seals. So I pulled the iron heads to look and found the gasket was not sealing well. The squinch part of the chamber was clean on #6&8. Coolant getting in somehow. So now I am going to go back with some aluminum heads and wanted to get the quinch right but alittle Leary of the shim gaskets. My deck if stock. It could be alittle out of shape idk. Victor graphite gaskets at 0.26 would put me at 51 quinch. If I could give up alittle I would feel better about the sealing with those. What do you think?
     
  10. jeff swisher

    jeff swisher Veteran Member

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    .051" I would not sweat it. My decks are always surfaced or milled if I run the steel shim .015" gasket and heads are also fresh and flat.
    I did a 355" last year with Edelbrock 5089 heads .. the pistons were .020" down the hole and he ran a .039" gasket that came in the KS2600 gasket kit.
    It is in a heavy chevy truck it likes a lot of timing 42 total for best ET and MPH go figure but it is only 1 tenth off of the ET with 38 total.
    That is running 91 octane and over 3900 lbs race weight.
    .230 @ .050 on a 106 LSA-.480" lift flat tappet.
    Bog out of the hole every time as he just got it going with what he had and I feel the Hurricane intake was a mistake on this deal.
    I tuned all night and he got 15 passes, 13.02's was all she had in her.
    Not bad for a daily driver truck bogging out of the hole every time.
    Drive like you stole it to the track 50 miles away and drive like you stole it on the way home.
     

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