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?
     
    73RivStage1 likes this.
  11. 1969RIVI

    1969RIVI Well-Known Member

    Does anybody know what gear sets and carriers fit into a 69 Riv 9 3/8 rearend? My chassis manual says it came with a 3.07 and the guy who did most of the work/mods on the car said that he put a 3.08 posi in it, but didn't mention where or what it came from.
     
  12. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    No new gear sets or carriers, just used, happy hunting.
     
  13. flynbuick

    flynbuick Super Moderator Staff Member

    67 to 70 Buicks with 9 3/8” rears.

    Rivs
    Electra’s
    Wildcats
    70 Estate Wagon
    70 LeSabre 455
     
  14. 1969RIVI

    1969RIVI Well-Known Member

    Hey flynbuick by chance do you happen to know the gear ratio options for those cars you listed above?
     
  15. flynbuick

    flynbuick Super Moderator Staff Member

    2.56
    2.78
    3.07
    3.23
    3.42
    3.91

    These are Buick 1967-70 9 3/8"gear ratios for which I see GM part numbers assigned. Whether these were listed as available on GM order sheets as an option is something I cannot address. All listed would have been available as over the counter parts while at least some would have been listed as options.

    For 65 only I see a 4.45 gear ratio set with a part number assigned. One of the rear gear specialists on this Board would need to be consulted about whether a 4.45 set could be used in a 67-70 carrier.
     
  16. Bigpig455

    Bigpig455 Fastest of the slow....

    To confirm that Fabcraft is currently making big car gears and the approach they are taking, just not for a 9 3/8 axle.

    So now people know they can and will if demand is there, and how they accommodate the fact that people want 3 series gears when there are very few 3 series carriers floating around. And for additional info, they intend to price them (and have in the past) at about 400.00. And those 8.75 axle assemblies will bolt right in to a 71-76 9 3/8 application if people are looking for a 3.55 ratio with whats currently available. And and and.....
     
  17. C.Rob

    C.Rob Well-Known Member

     
  18. Jaquan

    Jaquan Member

    I have a 1961 buick lesabre



    I have a 1961 buick lesabre 4 door sedan what is the specs for my rear if you dont mind me askn
     

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