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Thread: 2 bolt studded mains versu 4 bolt main conversion on 496

  1. #1
    Junior Member APPRENTICE
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    Apr 2006
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    15

    2 bolt studded mains versu 4 bolt main conversion on 496

    My engine builder claims I can save about $500 if
    I just have him install a 2 bolt ARP stud kit on my block
    rather than have my current 454 2 bolt main block machined for a 4 bolt main cap conversion.
    He already purchased a complete Eagle competition rotating kit.
    The pistons are "JE" about 12 1/2 to 1 with my current GM 990 cast iron heads.
    My Long range plans call for Dart oval port heads / intake.
    I don't plan on going past 6,500 thu the traps.
    Am I making a smart or stupid decision?

  2. #2
    Senior Member DYNO OPERATOR
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    VA Hospital, Dallas, Tx (214 302 1924) cell-972-464-7400
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    I agree with your machinist.

    Yes splayed caps are better and are stronger. 4 bolt caps are nice to have in there. No doubt both are better.

    BUT!

    Back in 1984 I ran 154 mph with a 2,960 lb car using great heads and a 2 bolt Main chevy car block with two sleeved cylinders as a 461 cu in 16.85 -1 compression , and I kept it at 8,000 rpm all the time. When I was done with it after it going a 7.87 in a 2300 lb x-top fuel car I sold the short block minus cam for $500.00 and it went in a front engined alcohol dragster and he ran it several years, so it must not have been hurt. In case you have not figured it yet, that is over 1,000 hp with a stock 2 bolt block.

    I would run it like your machinist suggests unless the money for the better caps is no big thing.

    Ed
    " Let all things that hath breath, praise the Lord. Praise Ye the Lord" Psalms 150 vs 6.

  3. #3
    Administrator RACING JUNKIE
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    I'd agree with what Ed is saying,I too have run a 2 bolt block with good results.

    Tom
    There Is 1 Thing Better Than Cubic Inches,,,More Of Them

  4. #4
    Senior Member RACING JUNKIE
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    san antonio, texas
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    for mild racing 2 bolts work, i had my machinist align bore a 4 bolt
    on my bbc, remember that crank is just trying to bust out of the
    block with alot of torque. 8)

  5. #5
    Senior Member RACING JUNKIE
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    May 2006
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    2,044
    I went one step further with my 454 2 bolt block, I installed studs and a main cap stud guirdle. Its an old small block ford trick but it really helps to stablize the bottem end and prevent cap walk. I scored mine with the studs and hardware for about 100 bucks on ebay. The studs are long enough that I can use a windage tray too. Charles
    ***IN GOD WE TRUST***

  6. #6

    Two bolt mains

    Quote Originally Posted by edvancedengines
    I agree with your machinist.

    Yes splayed caps are better and are stronger. 4 bolt caps are nice to have in there. No doubt both are better.

    BUT!

    Back in 1984 I ran 154 mph with a 2,960 lb car using great heads and a 2 bolt Main chevy car block with two sleeved cylinders as a 461 cu in 16.85 -1 compression , and I kept it at 8,000 rpm all the time. When I was done with it after it going a 7.87 in a 2300 lb x-top fuel car I sold the short block minus cam for $500.00 and it went in a front engined alcohol dragster and he ran it several years, so it must not have been hurt. In case you have not figured it yet, that is over 1,000 hp with a stock 2 bolt block.

    I would run it like your machinist suggests unless the money for the better caps is no big thing.

    Ed
    I can't top your feat Ed, but we ran a 475 for three years using a two bolt main pass car block with an ARP stud kit, Eagle crank and rods, JE pistons with 14.5 to 1 compression. Dart 310 heads. 821 HP on alky. Car weight was 2731 and we ran it hard, 8000 rpms through the traps. No problem with it at all. The only reason we stopped using it was the bores got wore to the point that we couldn't hone it clean anymore. And we did have a heating problem with it if we had to idle too long at the line or staging lanes that we decided not to use it anymore. (Was told that the cylinder walls too thin is what caused the heating problem.)
    But the block with the two bolt main held together just fine.

  7. Racing Junk


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