4x4 or 2wd?
if 4x4 then agree on then 4bt, and keep everything stock.
go 6bt in the 4x4, go 14b rear, and get matching front outers, should hopefully have a ( WHAT TRANS) to a np205 tcase.
if 2wd go to junk yard buy front springs from a 3/4 or one ton, then buy a rear axle 14b prefered and go with the 6bt.
6bt around here run almost half the cost of a 4bt, are in bigger quantities.
Now that i think about it the 14b rear might not be a bad idea with either motor, in any above configurations.