9 3/8" rear differences

Discussion in 'A boatload of fun' started by quicksabre, Apr 22, 2005.

  1. flynbuick

    flynbuick Super Moderator Staff Member

    I am pretty sure that the whole axle housing from another 71 or 72 Buick Riviera will interchange. I am unsure about whether another 73 Riviera will.
     
  2. David Brown

    David Brown Member

    I know the 71-73 will. I see sites that say s GM will fit and I was trying to confirm.
     
  3. flynbuick

    flynbuick Super Moderator Staff Member

    I do not know what you means by "GM". I do not think there is another donor model other than a 71-73 Riviera. The reason has to do with other aspects of a particular model's housings, like spring perch locations and so forth.
     
  4. RoadShark

    RoadShark Well-Known Member

    That is what the Hollander Interchange Manual says. It used to be the Bible for interchange before the internet came along. I haven't confirmed any of that and have no first-hand knowledge, just thought I'd give you a starting point.

    What I posted is for the housing and has nothing to do with the internals.
     
  5. flynbuick

    flynbuick Super Moderator Staff Member


    Bill--Thanks for looking this up. I had not noticed your post.
     
  6. David Brown

    David Brown Member

    I have found a company that has an orginal 71 boat tail complete axel with a 9.3/8 ring gear posi. Problem is its in a 2.9 ratio. I was told it was a special order item you could ask for that year. Problem is ive never heard of a 2.9 posi that year.
     
  7. flynbuick

    flynbuick Super Moderator Staff Member

    It was not a special order ratio. 2.9 = 2.93 ratio to be precise. This is the standard, and most common, ratio used by a 71 non-GS Riviera.
     
    Last edited: Apr 27, 2018
  8. David Brown

    David Brown Member

    that was my thought as well. Now to figure out if they have a peg leg or a 3.42 that they think is a 2.93. thanks.
     
  9. Bigpig455

    Bigpig455 Fastest of the slow....

    I've spoken to the folks at Fabcraft.. they ARE making a run of 3.55 gears for the 8.875 Pontiac rear. The gears will be made extra thick to fit the 2.93-3.23 carrier break. Dont know when they are goingt o run them, but probably soon.
     
  10. flynbuick

    flynbuick Super Moderator Staff Member

    How does this relate to the 9 3/8” rear parts shortage?
     

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