Does this valvetrain geometry look ok?

Discussion in 'Engine Topic' started by fstarocka, Jan 22, 2021.

  1. G72Zed

    G72Zed Veteran Member

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    Good points by 1320feet.

    I will add, the +.100 longer valve is adding to the issue as the tip is now closer to the stud center-line.

    Also, although a great video on the "Mid lift theory" and attaining it's geometry, it's a BBC, your working on a SBC, with a stud mount arrangement, and this generally favors the "low pivot" option.

    Crower do make .090 backset trunion RR for this setup. I think they are not cheap at $380 for a set of 8. So get out your wallet on that one for sure.

    The last thing I buy is the push rods as you do not know what length you need until it's all assembled. And use your real springs for final checks and patterns.
     
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  2. 77 cruiser

    77 cruiser Veteran Member

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    You can try the maker method & trying different PR lengths till you find the narrowest pattern.
     
  3. fstarocka

    fstarocka Member

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    Ok i finally managed to get it done RIGHT! pattern is TINY, like 45 thou. I needed longer rocker studs and all is good! Im very happy - upgraded to 3/8 pushrods at the same time. Ill use the 5/16 parts for my milder 400hp 350 build -
     
  4. sandlapper

    sandlapper Veteran Member

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    [​IMG]
     
  5. G72Zed

    G72Zed Veteran Member

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    Good to hear this news that it's worked out for you in the end, .045 width pattern is nice, and the jump to the larger 3/8 diameter pushrods has no downsides other than fitment in some cases, but it's worth it.
     

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