The above-mentioned inaccuracy in the Tech Chart sent me looking for a 71-74 B-body rear to put in my 68 Fury. The Tech shows the B rear to be about 3/4" narrower than the C (and with similar perches), so I figured it was perfect for some slightly fatter tires.

When I finally found what was reportedly a 71-74 B-rear, it was immediately noticeable that it was wider than the C-rear. At least 2" per side??? Didn't even have to measure it nor compare it to a C-body rear.