The couple sets that I’ve personally come across were on 65-66 C-bodies. I think they came on some of the B’s as well but that may have been due to a production issue? I have a couple of those earlier C-body 8 3/4’s because they used to show up in the yards more often than any other 8 3/4 and they’re a bit narrower than the van and truck 8 3/4’s.
As for re-doing them, best of luck. Most of the 11x2.5” hardware should work, but I know the few times I’ve looked into it the drums and shoes haven’t been in production.