1. Jim Kueneman

    Jim Kueneman FABO Gold Member FABO Gold Member

    Messages:
    2,186
    Likes Received:
    4398
    Joined:
    Jul 26, 2016
    Location:
    Sonoita, Az
    Local Time:
    3:18 AM
    I am using the stock leaf springs in the '72 Duster and have a pre '68-'70 8 3/4" for it. The perches have been cut off and new ones ready to install. Am I safe expecting with stock springs where the perches sit to be parallel with the bottom of the car? So can I safely align the perches with a -8 degree (with respect to 90 degrees) or so angle to the face of where the center chunk bolts to and have it come out fairly close to -8 degrees when all together? I don't have the K-frame and power train in the car yet and would like to get the rear axle done before that happens.

    Thanks.
     
  2. DoctorDiff

    DoctorDiff Well-Known Member

    Messages:
    319
    Likes Received:
    262
    Joined:
    Sep 30, 2012
    Location:
    Polson, MT
    Local Time:
    3:18 AM
    An 8 degree negative perch angle will bind the U-joints.

    If you want to duplicate the stock A-body pinion angle, weld the perches at 43" on center. The pinion should angle upward 5 degrees when the perches are level with the ground.
     
    • Like Like x 2
    • Jim Kueneman

      Jim Kueneman FABO Gold Member FABO Gold Member

      Messages:
      2,186
      Likes Received:
      4398
      Joined:
      Jul 26, 2016
      Location:
      Sonoita, Az
      Local Time:
      3:18 AM
      Thanks, I swore I read it should be angled down (maybe that was for maximum traction drag racing). Thanks. I have and order in your cart for reseal kits, brake lines and brake hardware once I go out and measure for the correct lines!
       
    • DoctorDiff

      DoctorDiff Well-Known Member

      Messages:
      319
      Likes Received:
      262
      Joined:
      Sep 30, 2012
      Location:
      Polson, MT
      Local Time:
      3:18 AM
      Pinion angle is relative to the transmission center-line, not to the ground. Even though the pinion appears to angle upward, it is actually 2 degrees negative when compared to the transmission.
       
      • Like Like x 1
      • Thanks! Thanks! x 1
      • Agree Agree x 1
      • Jim Kueneman

        Jim Kueneman FABO Gold Member FABO Gold Member

        Messages:
        2,186
        Likes Received:
        4398
        Joined:
        Jul 26, 2016
        Location:
        Sonoita, Az
        Local Time:
        3:18 AM
        What brake hose will reach from the '72 Duster hard line bracket to the junction block on a late '60s 8 3/4". It is the one that has the block closer to the center of the axle.
         
      • j par

        j par Well-hung Member

        Messages:
        28,353
        Likes Received:
        16250
        Joined:
        Jul 2, 2014
        Location:
        Portland Oregon
        Local Time:
        2:18 AM
        Or like maximum vibration drag racing! LOL:poke:Dr diff has spoken on the subject nuff said...:thumbsup:
         
      1. This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
        By continuing to use this site, you are consenting to our use of cookies.