That's odd, 3.73 is most popular ratio, and 7.5" most popular size.
Local or semi-local wrecking yard should be able to get one in for you.
All 1983-1992 Ford Rangers used them, '93 and up were wider, but internals were the same, all were 28 spline axles, 4.0l got 8.8" '90-'92, then wider in '93
Bronco IIs '84-'90, used same internals, 28-spline, but axle was longer on 1 side
Most 4x4's had L/S in the rear.
Aerostars('85 and up) and Mustangs('79 and up) also used 7.5", 28-spline although L/S would be harder to find