School me on closed knuckle interchanges

[carnuck]

On my '68 Travelall I have a D44 closed knuckle front (4.10s) and my '73 J4000 had the same (3.73) I would like to swap the knuckles from one to the other (if it will work. I don't know if they will interchange). I heard the IH axle may have negative caster built in (I read that someplace a long time ago)
The Jeep axle is the same spring pad width so I could bolt it directly in but then I'd have to do gears (not my forte and I hate gear lube to boot)

The reason for the swap is the IH steering SUCKS! Old Chev style with the short arm on the driver's side so bump steer is EXTREME and the worn out IH manual box (It skips!) made for a scary ride, even at low speeds! I'm putting in a Ford 4x4 PS box from a '77 3/4 ton with the Jeep crossover tierod. The Jeep knuckle has 2 spots for tierod on the pass side and the old tierods from the J4000 are still in good shape.

Any thoughts? (yes, I asked the IH guys and got crickets)