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
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
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
You should be able to identify whether it is the Pontiac (BOP) rear or the 8.5. Just look at the rear u-joint to yoke attachment. http://jdrace.com/content/diff_id/10bBOP_Pontiac.php http://jdrace.com/content/diff_id/10b85.php
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.
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
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
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.
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.