Mid 60s C-Body 8.75 axles... cant shorten them?!?

Supposedly the case hardening extends down the axle into where the new splines are cut so there's still some strength there but cutting new splines into a case hardened shell won't be as good as the factory roll forged splines.
As a previous poster stated,they probably won't stand up to drag race starts with slicks but are likely fine for mild street cars on street tires.Personally I can't picture my 273 2bbl stripping splines off any kind of rearend never mind an 8 3/4.