Hello - ok, heres the problem. My stock axle needs some tlc and its looks to be a bit pricey, not to mention I can't source adjustment shims. Has crossed my mind to go 8 3/4 but don't really want to lose my band brake. Thought about cutting the drive shaft ( a spare one ) and welding a yoke on to only one end. Am I crazy?

Not the way I would go, but there's no reason it wouldn't work.

I've installed an 8-3/4 rear under the G/Friends 55 Desoto. An E-Body was a direct bolt in.

What did you do on the transmission end? Did you retain the original tranny?

No, I installed a later model 904 Torqueflite so it has the later style slip yoke.

I don't see any reason you can't swap in a u joint end on your original drive shaft. The mid 60s Mopars have the tronion at the front and a u joint at the rear on most drive shafts during 64 & 65 when they were changing the transmissions from the cable shift to the rod linkage. Gene