The GM 14 bolt from a “cab and chassis” truck is best axle swap in my opinion.
Width is perfect, lots of gear ratios available, some even faster than practical.
Brakes are large, available, and economical.
Spring perches do need moving. Better to replace with aftermarket bent steel ones that match spring width.
Brakes as they come just fit, but replacing drums with shallower offset ones (use same brake shoes) and welding on a new flange for backing plate to bolt on a little further out makes for plenty of room between brakes and springs.
