Rear end and bolt pattern

Hey guys. Just curious on the change to the big bolt pattern? I would like to find a 8 3/4 rear end but did they ever come with big bolt pattern and what vechicles would i find this in? Or is it cheapier or better to get a 8 3/4 and put in the axles? To do the change up on the drums to disc on a what type of donner car would i need and with the big patter? Is there a book with all the interable parts for a 67 dart? thanks!!