Looking for options to do a 4” to 4.5” bolt pattern swap all around and brakes.

I have always upgraded to 73-76 A body front disc set up & 8 3/4 rear 10 in. drum with NO power booster, that way I don't have to worry about low vacuum at idle, go to doctor Diff and look what he has & call him if you have questions, great customer service. I buy some parts from him just not kits because I look for deals, it just takes time to find, and you have to clean old parts. Nice looking cars. If you go with 8 3/4 you can change gears sets to have some fun or for freeway long distance trips. If you go with 8 1/4 just pick gears for the type of driving, you plan to do. both rears are getting hard to find.