Pushrod diameter decision

Discussion in 'High Tech Retrofits' started by 70PTRS, Aug 6, 2014.

  1. 70PTRS

    70PTRS Veteran Member

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    Alrighty I'm currently putting together my motor, here's the specs:

    02 5.7 stock bottom end
    243's full cnc porting 226cc by AI, milled to 61cc
    226/234 113 LSA 600/600
    Stock rockers with trunnion upgrade
    Ls7 lifters
    BT springs
    Ls6 manifold

    Should manage around 440-460 rwhp

    I measured with the pushrod checker last night and I'm going with 7.300 length pushrods. I get 4130 chromemoly 5/16 x .080 wall thickness pushrods with my order from Ai but read where a larger dia pushrod is much more robust for valve geometry. Is going to a 11/32 dia or 3/8 dia worth the extra cost or is it overkill for my motor? I'll probably take the car to the strip a couple times a year, shifting around 6500 rpm.

    I could have had them open up the hole for more clearance but wasn't aware of the larger pushrod dia at the time.

    Going to an 11/32 dia PR would cost 80-100 bucks more than the 5/16s

    I want to order them tomorrow so quick opinions are much appreciated
     
  2. TheMeat

    TheMeat Veteran Member

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    I've got the 5/16 in my junk.

    BTR springs and cam.


    Doesn't look like you have anything crazy in it lift or spring pressure wise. I would run with what you got.
     
  3. 71RS/SS396

    71RS/SS396 Veteran Member

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    I would stick with the 5/16's, bigger is stronger but also heavier which is never good when it comes to valvetrain components imho.
     
  4. mrvedit

    mrvedit Veteran Member

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    I have COMP 5/16 with dual valve springs with 400lb open pressure on cam with .624 lift. I have revved this to 7000 RPM hundreds of times.
    If I had 500 lb open pressure I would get stronger push rods.
     
  5. APEowner

    APEowner Veteran Member

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    You probably already ordered them but you'll be fine with the 5/16" pushrods with that cam and those springs.
     
  6. 70PTRS

    70PTRS Veteran Member

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    Nope; didn't order them. Will use the extra 100 bucks for something that makes more sense.
    5/16's it is.

    Thanks for the help :)
     
  7. 383Camaro79

    383Camaro79 Veteran Member

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    dont need bigger diameter pushrods unless your running crazy high spring pressure, you shouldn't be at 500hp
     

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