9 1/4" Axle Swap?
Most 73-76 A Bodies with a V8. Some slant sixes will have them, too. I'd just start looking under whatever 73+ A Body you see to see which axle it has.
Be sure to get as much from the donor car as possible. The axle tubes are larger than on a 7.25. So get the U-bolts and nuts, and the shock plates.