Found a 8 3/4,but have a question

I finally found an 8 3/4 rear,complete with brakes and everything.The thing is,its going to come out of a 78 Dodge Aspen.What would I have to do to put this in my 72 Duster?(what mods ,oris it a direct bolt on?)The car also has a 318 with a 727 ,and he said he might throw in the drive shaft too.