push rod lenght

Discussion in 'Technical' started by BIG T, Aug 20, 2014.

  1. BIG T

    BIG T Member

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    Hello, would like to run a 91 5.0 short block with my 1971 heads. What length push rods do I need

    Thanks
    Tony
     
    BIG T, Aug 20, 2014
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  2. Bryant

    Bryant forgot more than learned

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    to many factors involved to be able to just know what length push rod is needed.
    is it a flat tappet cam or roller cam?
    has the block been surfaced?
    what cylinder heads?
    have the cylinder heads been surfaced?
    has the cylinder heads had a valve job?
    has the valves been replaced?
    what rocker arms are you using?
     
    Bryant, Aug 20, 2014
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  3. oldsnut

    oldsnut Member

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    I would suggest a push rod length checker to maker sure you get it right.
     
    oldsnut, Aug 20, 2014
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  4. garrettmuir1227

    garrettmuir1227 (Almost) Certified to Work on Your Porsche

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    agree. save yourself and get a pushrod length checker. well worth the cash. take it from someone who did it the hard way.... long story short i have 4 sets of unused pushrods at home...
     
    garrettmuir1227, Aug 20, 2014
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  5. rotorr22

    rotorr22 Member

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    Its really not that difficult to use an adjustable pushrod to establish the correct length. If you are running a hydraulic roller, you will have to modify a lifter so the plunger does not depress when you rotate the engine through a valve cycle. I bought and modified spare lifter to accomplish this and can use it as a tool if I modify the engine in the future.
     
    rotorr22, Aug 21, 2014
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  6. Krazy Comet

    Krazy Comet Tom

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    Pushrods used with stock roller lifters are 6.27" and with flat tappets are 6.8", though 6.9" generally gives better geometry with roller rockers... As suggested with the mix of parts, length should be measured...
     
    Krazy Comet, Aug 21, 2014
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