4 Speed manual overdrive transmission for A body

I think you mean the c/s .
Behind a regular SBM; if you keep good oil in it, they will wear out other parts long before egging out the c/s hole. And if that does happen, then, any automotive-machine shop can bore that hole out for you and press in a bushing. It ain't even that expensive.
The counter/shaft pin never spins, It is locked. The counter shaft gears ride on needle bearing sets that ride on the shaft.