Wanted to confirm some information on the 8 1/4 rear end (carrier swap)!

Very surprised that Dr.Diff would say their is only 1 housing for the 8 1/4. 1973 thru 1975 used a carrier race that had a diameter of 2.891. 1976 and latter differentials used a carrier race diameter of 3.062. Some of the late 1975's had the larger size.
Correct, but that doesn't change the housing.