[Mister Pontiac]

Recently I swapped the rear end in my 67 Tempest Wagon to get more highway friendly gears. After sourcing a correct 67 vintage 8.2" with a 2.56 Posi, I set to work swapping the rear out.

After pulling the 10 bolt in the car, I decided to swap covers as I wanted the old chrome cover on the replacement rear as well. Only then did I realize I had something different. The bolt holes on the cover didn't line up. As I stared at things for a minute, it finally dawned on me... I had pulled an 8.5" and was installing an 8.2". With my trusty tape measure, I confirmed my suspicion.

This was a pleasant surprise, as you might imagine, and now I have a spare 8.5" with a 3.23 Posi that works well. I have a feeling it will find its way under my 72 LeMans GT pretty soon.

But here's where I get to my question(s)... I had actually pulled this 8.5" from a 71 LeMans about 20+ years ago, and installed it in my wagon about 18 years back. At the time, I didn't know the difference between the two sizes, and simply installed it as a "10 bolt 3.23 Posi." Who knew.

So tell me... did Pontiac ever put an 8.5" in one of our beloved A-bodies? I have been under the impression these were found only in Buick's or Old's, not Pontiac's. Is this correct? If so, the LeMans I sourced it from back in the 90's had pirated it sometime before that from something else. Interesting!

Second, I know the 8.5" is stronger than the 8.2", but compared to a 12 bolt, are we talking about a step in between 'strength wise,' or are we comparable to the 12 bolt?