Pinion angle affected by trans mount

Discussion in 'Street/strip 400/430/455' started by Skylard, Apr 3, 2017.

  1. Skylard

    Skylard Well-Known Member

    I'm wondering how much the height of the transmission tail affects the pinion angle.
    What do you know?

    Cheers!
     
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Measure it with a cheap angle finder from Sears.
     
  3. bignastyGS

    bignastyGS Maggot pilot

    or harbor freight
     
  4. rmstg2

    rmstg2 Gold Level Contributor

    Have you driven it with the new mount? If it doesn't vibrate it is probably in the ballpark with the new mount. Pinion angle changes all the time while you are driving as long as it isn't to far out it should be OK.



    Bob H.
     
  5. Skylard

    Skylard Well-Known Member

    I race the car and just want to know what it is.
    where is the measurement taken from?
     
  6. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    You measure the angle of the transmission's tail shaft and call that zero, you want your rear end pion to be pointing down from the zero negative 1.5* plus or minus 1 degree. That is the sweet spot with a factory 4 link rear suspension for drag racing.

    Brake torqueing at the starting line(with an auto trans) will preload the drive train and with the angles setup as mentioned should make the rear wheels plant to the pavement when you launch.

    Not very easy to adjust the angle with the factory non-adjustable control arms, you can shim the trans mount up or down though to try and get your angle closer. Otherwise you will need to get a set of adjustable upper control arms. GL


    Derek
     
  7. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

  8. 67skylark27

    67skylark27 Brett Jaloszynski

    I used my smartphone and downloaded the free Tremec app to get pretty close.
     
  9. BrianTrick

    BrianTrick Brian Trick

    One thing to note: If any of you guys buy the urethane trans mount,it comes with a plate that is supposed to be installed with it. Leave the plate off. It raises the tail too high,and you will likely be chasing a vibration problem,due to shaft misalignment. The mount itself is thicker or taller than the rubber mount,and that additional plate is just too much.
     

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