I think they would hold up more than a 8.75 but they're c-clip axles, so custom axles & new green bearing ends, I can't remember which ends work, it is a decent sized pinion 1.7/8, they're super easy to rebuild but only 6 gear sets 3.21-4.88 I believe, there's a 67-69 valiant a guy is doing a turbo magnum he narrowed 1 and I'll see how it holds up.