Building my first 8.25 rear..
The carrier bearings changed in 76, the OD got bigger but the ID stayed the same. If your trying to put a newer carrier into an pre-76 rear or vice-versa you will have to use the right bearings for the rear that you are working on. I dont see why a 2.76 and up carrier wouldn't fit in a 2.45 housing, I always thought the 2.45 gears wouldn't fit into the 2.76 housing because of the massive pinion gear.