I have a 72 Buick Skylark GS with a 8.5" posi rear and 2.56 gears. I would like to upgrade by installing a 80's Buick GN 8.5" posi with 3.42 gears. The 72 GS has bolt-in axles while the GN does not. Can the GN posi be installed in the 72 GS rear and still rertain the bolt-in axles? If the GN posi does not work, I also have a 79 TA posi with 3.23 gears. Would one or bolt work in the GS rear end while retaining the bolt-in axles? Thanks for any input.

Yes the GN 8.5 posi will work in the '72 rear end. Keep the bolt in axles. Do you have the complete GN rear end?

I do not have a complete rear end. Big gear head, thanks for your assistance.