Back spacing on B body rear end in 73 Duster

5/16" per inch on each side. So figure a ~5.75 BS to get the wheel centered.

Thanks, I bought a set of centerlines off of a friend and member here weeks ago. They are 15x7's with whatever the standard backspace is 3/38's or something like that. Look ok with the stock 8/14 rear but since I decided to change out the rear diff, I may go with something more from what I've found that this diff will push the tire out a little further towards the quarter so that would give me more room towards the spring. Once the diff is done and I can install it and the axles then I will know what my options are. 5.75 would be great to get more tire under the car.