I had this Dana 60 603222-1 9-15-70 B7 The dates on the chart aren't perfect and it wasn't used in 70 but this was a 3:54 Trac-Lok out of a 71 B body. 70's had power lock's. This is the longest and rarest factory Dana.

I'm guessing Cudakid's rear might have been a leftover housing that was never installed in a car. Picture is the Bbody rear next to new S60 E body. The B body Dana is now happily living back in a 71 Hemi B car in Canada.