69 B body 8 3/4 in a 68 A body with 15x7s?

Okay so I haven't had any sort of a chance to measurements (and I know people run the Ford off set with this combination) but I have an 8 3/4 from a 69 B body (that I've already moved the purches) that I plan to run in my 68 valiant. I picked up a set of western wheels that are 15x7 with 4" bs. I was thinking of running a a 255/60R15 in the rear. So does anyone know if it will fit without narrowing the rear?