There are at least half a dozen full floating rear axles that are very close to the right width, with the exact same 8 bolt lug pattern. Dana type 60 and GM corporate 14 bolt are the most common - - - -in Ford, Dodge, GMC, International, and a few other brands of trucks. There's absolutely no reason other than bullheaded stubbornness to stick with the Eaton 3/4-1 ton housing. I've got a mid-1970's Dana 60 from a GMC with a 3.73 gear ratio and a Positraction center section under my 59 Burb right now.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!