hello all new here,has questions :) lol

rears- 63-76 will bolt in. but some have a 4" bolt pattern and some have a 4.5" bolt pattern. your 72 will have a 4"

bell housing. - yes 6cyl, small block and big blocks all have different bell housings..

15" wheels- aftermarket only if its small bolt (4")

slant to small block you can use conversion mounts from schumacher www.engine-swaps.com or change over to a v-8 k-member..