73 Apollo Rear Axle

Discussion in 'The "X" bodies' started by Stagedcoach71, Sep 19, 2016.

  1. Stagedcoach71

    Stagedcoach71 Well-Known Member

    All:

    I have begun my 73 Apollo Project. I have a 350 built by AMP to drop in. I am also going to put an OD transmission in.

    The car has a posi from the factory (or so says the cover tag). Is this axle worth updating the gears in or should I pick a stouter unit. The motor was dyno'd at 365 peak HP and 400 lbs of torque.

    I would like to go 3:73 given the OD transmission. However, is the 73 Apollo axle strong enough to pound on, even a sticky track?
     
  2. steve covington

    steve covington Well-Known Member

    If your rear is 8 1/2" , you should be good to go. The 8.5 is ALMOST as strong on the pinion as the fabulous 12 bolt (8.875 actual gear size). If I recall correctly, the pinion diameter are the same for the 10 bolt 8.5 and the 12 bolt 8.875. That said, I think that the Nova/ Omega/ Ventura/ Apollo rears could be either the weaker 7.5 inch or stout 8.5 inch. Easy way to ID the difference between 7.5 and 8.5 is 78.5 rears have basically 90 degree (right angle) castings at the bottom corners with round covers, while the 7.5 rears have roughly 45 to 60 degree corners with oval covers. Problem is, same as with the Chevy 12 bolt rear, they are C-clip style rears. For piece of mind, you need to have C-clip eliminators...
     
    Last edited: Sep 21, 2016
  3. Stagedcoach71

    Stagedcoach71 Well-Known Member

    Thanks Steve.

    I'll poke my head under the car after work.

    Hopefully I'll have the stronger unit.
     
    Last edited: Sep 22, 2016
  4. Stagedcoach71

    Stagedcoach71 Well-Known Member

    A couple of pics. The cover seems round to me.
     

    Attached Files:

  5. steve covington

    steve covington Well-Known Member

    Double good news! 8.5 AND limited slip (AKA posi). This rear has readily available upgrades and parts availability. Just a plug for Monzas here on the board, should you need parts, gears, or just advice.
     
  6. wkillgs

    wkillgs Gold Level Contributor


    Yup, matches the pic on his ID page! Check out his website here:

    http://www.jdrace.com/diff_id/10b85.htm
     
  7. sean Buick 76

    sean Buick 76 Buick Nut

    The 8.5 rear is still holding up fine in my twin turbo 350 car:

    [​IMG]
     

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