Rear end

Is this a option?
Take the guys out of the Jeep rear and use it in the one you have?
guessing you meant "take the gears"....

not sure if there were any differences/changes that happened between the early 70's and early 90's that might preclude that....IIRC there were some major changes to the 7.25" in the late 70's that made stuff like that not swappable.