9in swap

I have a 1968 Mustang coupe that has been in the family since it was new off the lot. The car was a I6 auto, and now has a small block v8 in it. I need to know what year and types of vehicle to get the following:

Front 5 lug disc brake spindles.
Rear 9in
tranny advice
drive shaft

Any help would be great. As far as the tranny goes i just need to know some advice on which one and how hard it is to put in or do a conversion on. I wouldnt mind going to a manual. Thanks to everyone...:worship