WHAT rear is this?

Discussion in 'Got gears?' started by 3.8Stoke, Jan 12, 2005.

  1. 3.8Stoke

    3.8Stoke Well-Known Member

    ok i have a rear end i got out of the junkyard here, it looks like an 8.5, has the two ears at the bottom, has an 1 1/4 pinion nut, 30 spline pinion, 28 spline axles, bolt in axles, ok now why is the biggest measurement on the ring gear i can get about 8 1/4 with a ruler. it came out of a 1970-1972 buick skylark, not sure what year, there was no front end, and back was trashed, at the base of the pinion bearing i got 1.625 and then it tapers down and goes back up to 1.315 its a 2.56 ratio open rear, Is this a normal 8.5 or whats goin on here
     
  2. 70 gsconvt

    70 gsconvt Silver Level contributor

    Sounds like an 8.5. Another tell tale that it's an 8.5 is to look at where the axle tubes go into the center section. If it is smooth all around, it's probably an 8.2. But if there are 4 "bumps", like at the 3,6,9,12 o'clock positions around the end of the center section, then it's an 8.5.
     
  3. flynbuick

    flynbuick Guest

    The last year for the 8.2 was 70. Post 70 US made were 8.5.
     
  4. 70 gsconvt

    70 gsconvt Silver Level contributor

    Pontiacs used 8.2 rears up to and including 1972 in the LeMans/GTO cars.
     
  5. 3.8Stoke

    3.8Stoke Well-Known Member

    here are some pics

    Whats is this?
     

    Attached Files:

  6. oPh

    oPh Well-Known Member

    3.8 Stoke,
    Pictures you posted are of the most common version of the '71-72 8.5 A-body housing.

    There are also two more versions of the '71-72 8.5 A-body rear built that had slightly different center housing... no big square lugs at 8 & 4 o'clock.
    :3gears:
    Roger
     
  7. flynbuick

    flynbuick Guest


    Since his question specified Buick my responsive post was related to Buicks.
     
  8. 3.8Stoke

    3.8Stoke Well-Known Member

    ok now can i use a c-clip style carrier on a bolt in?

    I notice that the carrier $ posi's i look at are for c-clip style axles, mine just bolt at the ends where the dust shields are, can i use these and leave out the c-clips?
     
  9. 3.8Stoke

    3.8Stoke Well-Known Member

    Anybody know?
     
  10. 70 gsconvt

    70 gsconvt Silver Level contributor

    If you have four bolts at the axle housing ends that hold a small plate in place right next to the axle bearing, given everything else you've said, you have a corporate, bolt-in axle 8.5 rear.
     
  11. GStage1

    GStage1 Always looking for parts!

    You can use c-clip 8.5 posi units in your rear. Congrats on the find.
    You can find the 8.5" posi carriers in any GM car/van/truck from 71-88. Most common in full size wagons from 80-88. Wagons usually have a good gear set like 3.08-3.42. See www.buickperformance.com/posi.htm for more info.
     
  12. 3.8Stoke

    3.8Stoke Well-Known Member

    Thanks everybody youve been a huge help, looks like this is gonna have to get put on hold, found nice size piece of frame rotted out last night, :af: so its gonna be a frame off for me. Anybody got a 69-72 a body frame handy?
     
  13. sevv

    sevv Well-Known Member

    Hey George,

    Scott from PA. I have a question, I hope you can answer it for me. I have a line on a 71 3.08 open 8.5 rear. Would this be a series two carrier? If so, how high of a ratio can I go?

    Thanks, Scott
     
  14. GStage1

    GStage1 Always looking for parts!

    3 series 2.73-3.90

    That (3.08) is a good ratio for a street car. I would get it and then find
    a posi for it.
     
  15. sevv

    sevv Well-Known Member

    Thanks George!
     
  16. JamesRS

    JamesRS New Member

    Pardon me for butting in on your post here 3.8Stoke, but I have a quick question about the 10 bolt that you have. ( I just found one exactly like it in a junkyard) What is the spline count on the axels? (I haven't had the chance to pull the axels yet) Is it 28 or 30? I want to go hunting for a posi and some gears better then the 2.73's that are in it now.

    Thanks.
     

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