72 Pontiac Lemans Rear Axle?

Discussion in 'Got gears?' started by Brent, Jan 4, 2023.

  1. Brent

    Brent Founders Club Member

    Experts, what rear end would be in a 72 Pontiac Lemans? Did Pontiac ever use the 8.5 or would it be an 8.2? If it would be a Pontiac 8.2, what parts are available for them? I have been using 8.5's for years, but they are getting nye impossible to find around here and I have a chance to get this Pontiac one. I even picked up a 12 bolt to build, if I can lower myself to using a Chevrolet, lol.
    Thanks
    Brent
     
  2. Bens99gtp

    Bens99gtp Well-Known Member

    A 72 Lemans should be an 8.5 if it hasn't been replaced....but 8.5s are easy to identify with a good picture from the rear
     
  3. nekkidhillbilly

    nekkidhillbilly jeffreyrigged youtube channel owner

    i thought some pontiacs had 12 bolts as well?
     
  4. BrianTrick

    BrianTrick Brian Trick

    Pontiac kept the 8.2” until very late 72 production,then phased-in the 8.5”. Not too many got them.
     
  5. Brent

    Brent Founders Club Member

    If it's a Pontiac 8.2, is it worth picking up? Can you get parts and are they decent?
    Thanks
    Brent
     
    Last edited: Jan 5, 2023
  6. BrianTrick

    BrianTrick Brian Trick

    Not worth as much as an 8.5”. What are you putting it behind?
     
  7. Brent

    Brent Founders Club Member

    Street car with a mild 455, more concerned about parts availability. Probably 30 years ago I built a Pontiac rear with 3.23 gears and it had a 4 spider cone clutch limited slip in it, had a hard time finding some of the parts then. The carrier looked pretty stout and it's still on the road in a GS with a 455.
    Thanks
    Brent
     
  8. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

  9. BrianTrick

    BrianTrick Brian Trick

    There are enough parts available for the Pontiac 8.2”. There are gears,posi units,and all of the bearings/seals are available. I would go through it before installing it. Always easier to work over it than under it. Jim at JD Race can service the posi unit as well for very reasonable cost.
     
  10. monzaz

    monzaz Jim

    Lemans rear ends and ALL BOP
    Seems GM was just stuffing anything they could under cars when 1972 hit...They were all concentrating on the new 73-77 line and oil crisis coming.
    I seen many 1972 Chevelle especially Monte carlos come off with 12 bolt chevy rears for mere 4 bbl 350 cars. AGAIN GM will not stop the line...Grab a rear and go.
    So if the Lemans was built on the same line as a Skylark or Oldsmobile and they ran out of Pontiac 8.2 rears I am sure the drive shaft and rear end from a Buick or Olds was popped right in.
    AS LONG as GM did not degrade a car... it was ok usually SO meaning NO chevy rears in BOP ever...lol. BUT in 1970 a lot of chevy cars got Pontiac and oldsmobile rears. AND proof is in the parts books in the auto stores. 1970 strike year.
    Jim
    JD Race
     
    Last edited: Jan 10, 2023
    sean Buick 76 likes this.
  11. Brent

    Brent Founders Club Member

    That LeMans turned out to be a 71 and it has a type O rear end, 12 bolt cover, Oldsmobile. Could that have come from the factory or was it swapped in? Anyone on here have parts to build it, posi and gears? I know they make new parts for it, but are they expensive.
    Thanks
    Brent
     
  12. BrianTrick

    BrianTrick Brian Trick

    I just built two of them over the weekend. Yukon makes a posi unit for them and Richmond makes 3:42 and 3:90 gears for them. They are not on the cheap side. Here is a picture of the part numbers for the 3:42 gears and the Yukon posi unit. You will need a longer driveshaft when swapping to the O-axle. It has the shortest pinion stem of all the rears of the era,thus needing the longest shaft to reach it.
     

    Attached Files:

  13. BrianTrick

    BrianTrick Brian Trick

    To answer the other question: NO. That rearend did NOT come in that Lemans from the factory. The 12-bolt O-axle was made from late-67 to 1970 and came under all Cutlass/442’s except the ones built in Canada. It might be somewhat believable if the Lemans was 1970 or older,but they were not making the 12-bolt O-axle in 1971.
     

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