I've got an 88 Centurion LeMans. It came equipped with a 6 speed Shimano Uniglide hub on the back. I replaced the freehub with a Shimano 7 speed hyperglide free hub & Shimano 7 speed cassette w/32 tooth extended range. Topped it off with a pair of 7 speed Shimano Tourney shifters. And, a long cage Shimano Deore rear derailluer. There were only a couple issues. One was finding the proper grease & dust cap seal for the new hyperglide free hub. The other was spacing. I wound up buying a slightly longer axle & putting a 2mm spacer on the drive side. With just a little spreading force, rear wheel fit between the stays fine. Didn't bother with any re-dishing. And, the end result is a wonderful riding machine. Be good. Have fun.