A stock steering box from any Wagoneer mid 70's thru early 80's will bolt up, but you'll need to drill and sleeve the frame to use the fourth bolt on the P/S box.
The boxes cast with a "76" seem to be the most desirable for strength.
As far as the pitman arm, it depends if you are stock ride height or lifted.
Do a quick search and you'll find plenty of info about different swaps others have done here and a lot of little details as well. I am sure other folks will chime in too with more particular details.
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