mocking up a new engine

Discussion in 'High Performance Modifications' started by jeff swisher, Oct 16, 2021.

  1. jeff swisher

    jeff swisher Veteran Member

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    I have a 350 .030 over 4 bolt block
    I pulled a balanced 355" rotating assembly from it and measured the cast pistons at over .050" down the hole.

    I have a stroker crank 3.75" in it now, mocked up and 6" crower I beam rods with 7/16 bolts.
    I had to grind quite a bit of the lower part of the cylinders to clear those bolts.
    I measured the piston do deck clearance and got .0265" at 3 corners and .028"
    at one corner.
    This is with Mahle pro true forged flat tops.
    I will assume this has never been surfaced or decked..Looks stock nasty.
    I will have .010" taken off both sides.

    The rods I got from the 350 rotating assembly are stroker rods also..Unknown brand.
    They are 5.7 with a bolt instead of a nut and bolt and alignment collars for the rod caps.
    They also have a dimple on the rod.
    Yea like a BBC dimple rod.

    Someone polished the beams on them also.

    Then hung cast pistons on those rods and left them .050+ down the hole and used a .039" head gasket and some 220 cc intake runner heads.
    It was a turd that a stock 180 HP 350 would out run.

    Moral of the story never assume your expensive forged pistons will be close to the deck.
    Measure everything.

    I did check cam to rod clearance with a few cams I have and the 6" crower rods have plenty.
    The 5.7 no name have plenty also.

    Fun stuff.
     
  2. jeff swisher

    jeff swisher Veteran Member

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    I just got the block and crank etc back from the machine shop.
    Had it decked and balanced.

    The owner told me he had to remove weight from the crank and stated your last piston rod combo must have been heavier than these ones.
    I had ran that crank in another stroker build.
    NICE!

    My old rods were the short 400" factory GM rods and pistons were cast sealed power flat tops 345NP.
     
  3. sandlapper

    sandlapper Veteran Member

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    Vintique 383
     
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