As far as I know only certain Dodge versions of the 60 will be a direct hub replacement for GM internal hubs. It seems that some Dodge external hubs were a different length than the internal Dodge & GM internal hubs.
I would think you would need to replace the spindle too if you have an odd ball length hub/spindle arrangement and check the stub axle shaft dimensions as well ( I remember changing to 35 spline stubs on a Dodge external spline hub and they were not the same length as the GM stuff ) .
Other than what is said above it should be a bolt on swap .
Good luck , Tom