Disc Brake swap-A body Rotors

Ditto to dgc's first paragraph. Since you already have an 8.75" rear, I wouldn't go through the effort to downgrade (in my opinion) to an 8.25. I'd get a pair of big bolt axles from Moser or Yukon and go that route.

If you do decide to pull out the 8.75, send it to me. LOL.