603051-3 is 69/70 C20 with coil springs. D60 rear with 3.73 open diff.
603054-3 is 68/75 IHC 1200 Travelall. D60 rear with 4.88 open diff.
So with that you tell us what it came out of.
In the future people, it helps to give a clue as to wether it is front or rear, D-60 or 44. cuts down search time. An if you can't tell the difference between a D44 and a D60 by sight, then........:flipoff2: