I’ve been looking for some reasonable sources on rear axle widths. Tough to get as people’s measurement methods can be different and often unspecified. Here are a couple decent sources:
My current rear axle in my Honda is too big and is from a 1957 or so Chevrolet. I did a really quick and dirty measurement of 54″ from back plate to back plate. That is about the max size I’d want from the outside of the drums. So it looks like a Chevrolet S10 2WD would do.
Some great S10 info:
A Chevette is a touch smaller (some sources say 2″) so would be even better. The torque tube may cause some issue however.
The Ranger looks ok but a little wider than the S10. The Ranger Station has some very nice information.