I ran a 51-54 Chev passenger 3:55 torque tube rear end from a powerglide for years in my '46. Requires some mods to mount to springs in a truck but easy to do. To keep 6 lug wheels, install the 3:55 tube in a 48 or earlier pass rear end.
Best of luck
Jim

Jim, I.I. #173
(It's easier to get forgiveness than permission!)