Any 4x4 700r4 should be a 27 spline output shaft, a TH400 would have a 32 spline output shaft.
So that means no matter what you do you need a NP208 or a NP241C passenger side drop that is a 27 spline input.
The transmission to transfer case adapter from a 92 could work, there may need to be an adapter to mount the tail mount support to, or even a new transmission cross member.
A complete drop in system could be had from a 1982 to 1991 square-body truck. Remember 1988-1991 was a dual year that had both square-body and the GMT400(1988-1998 style)
The best 700r4 case are typically found in 1985 and later trucks, there are also several internal upgrades that outperform earlier transmissions.