Will a 71-72 10 bolt fit a 1966 GTO?

Discussion in 'Got gears?' started by Canadian GS 350, Mar 15, 2019.

  1. Canadian GS 350

    Canadian GS 350 Well-Known Member

    good friend has a 1966 GTO 4 gear. Will a 1971-1972 10 bolt be a bolt in?
     
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    I believe so. Might need to shorten the drive shaft. You are talking about a Buick 8.5 10 bolt, right?
     
  3. Bigpig455

    Bigpig455 Fastest of the slow....

    it will - I threw an 8.5 in my 65 GS, works great. Width is fine with anything short of super wide tires, and with a ST300 trans I was able to use a 71-72 Buick Skylark sedan driveshaft. The driveshaft needs to be about 3/4 inch shorter, so look online and you can probably find the right application somewhere
     
  4. Canadian GS 350

    Canadian GS 350 Well-Known Member

    Is the 71-72 10 bolt slightly wider from backing plate to backing plate ?
    Thanks
     
  5. Canadian GS 350

    Canadian GS 350 Well-Known Member

    Buick Olds or Pontiac 71-72 A body rear......believe they all have bolt in axles?
     
  6. BrianTrick

    BrianTrick Brian Trick

    Is it wider? NO. Same exact width
    All of the mounting points are the same.
    As stated already,when swapping from the B/P 8.2” 10-bolt,to the 8.5”,you will need to shorten the driveshaft 3/4”. Same 3R u-joint.
     
  7. Canadian GS 350

    Canadian GS 350 Well-Known Member

    Thanks gents
     
  8. Bigpig455

    Bigpig455 Fastest of the slow....

    I have heard they are wider than the 65-66 BOP rears, but only by like a 1/2 inch or something really negligible....I think they are the same width as 67-up rears, but take all that with a grain of salt, I've never measured.
     
  9. BrianTrick

    BrianTrick Brian Trick

    The BOP rears were narrower for 64-65. They went wider in 66,through 72.
     
  10. Bigpig455

    Bigpig455 Fastest of the slow....

    ahhh - I knew it was something like that
     
  11. Canadian GS 350

    Canadian GS 350 Well-Known Member

    Just checked his rear against mine.......exactly the same 66 versus 72.....just as you’ve all said.
    Thanks
     
  12. newmexguy

    newmexguy Well-Known Member

    This was lying at the local yard a few years ago. It may still be there. Believe it is a '66 Pontiac rear.
     

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  13. Canadian GS 350

    Canadian GS 350 Well-Known Member

    Thanks - he’s looking at an 8.5 from an olds or Buick - bolt in axles
     
  14. BrianTrick

    BrianTrick Brian Trick

    Where is he located? I have them. I can build whatever he wants.
     
  15. monzaz

    monzaz Jim

    When Pontiac came out with the diagonal converging upper webbing they were all 55.25 wide. WIDE TRACK PONTIAC...
    Buick follow suite also. The only narrow Pontiac rear was the 65 it had one vertical webbing next to the pinion snout on the passenger side. The casting number was on the BOTTOM of the cast case.... So you would have to lay on your back on the ground and lift the rear end up and slide under the car to see it. 64 rears had the small 1" upper control arm bushings so those were easy to spot. 64 - 65 narrow 54.25 the rest were 55.25 in BOP 66-72.
    NOW that being said I am sure GM plants could have tossed up a few Very early 66 chassis with 65 width rears by accident or them trying to unload over stock parts.... You never know .

    Jim
     
  16. Canadian GS 350

    Canadian GS 350 Well-Known Member

    Guys - thanks for replies. He has located a 71 Buick 10 bolt 8.5 up here in vancouver. As you have said - it’s a direct bolt in to replace his 8.2
     

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