Identifying 73 and up disc brakes

They are not B body because of the caliper mount. B bodies used pins to retain the calipers. I'm with "everybody" Use them. You an buy larger calipers I've forgotten the application but I see no need to. One decision is whether to mount them caliper to rear or caliper to front. Caliper to rear gives you some more clearance if you use an anti roll bar, and then you must use different hoses, and swap the spindles left to right, and then make sure the calipers are mounted with bleeders up.