You never know what has been swapped in and possibly be a non factory made up unit, so also keep in mind that the pre-1964 8 3/4 rears were of tapered design which held the brake assemblies in place by the use of a key and locknut. This is not to say that other older rear end designs or from non a body vehicles vehicle can not be used, but just be aware of the differences so you can make informed decisions. A couple of links with good information.
