The 90* bell housing is too large to fit in the trans tunnel, and no one makes an adaptor for it. I don't know who does, but I agree with Mark (Maniac) about purchasing one from Bowtie Overdrive, DON'T. They put a drag racing shift kit in mine, then denied it when it was discovered as the reason it would not shift correctly no matter what we did.
I am running a NP231 transfer case with a shifter and cable from a 90's S-10. The trans output is a 4 bolt square pattern, transfer case is a standard six bolt round pattern. My adaptors are both from Advanced (Ford 4.0 to 60* 700R4 to NP231). I really like the transmission to transfer case adaptor because you can mount the rear trans mount on the adaptor, which is much stronger than the transmission mount. It also acts as a clocking ring for the transfer case. Before I went SAS, the t-case was sitting nearly flat way up above the frame rails. After the SAS, I had to clock it down one to get a better angle on the front drive shaft as the double cardigan was binding slightly at full driver side drop.