I just did this on an '87 with factory NP208 and SM465 32 spline, hydro. I waited till I found an SM465/NP205 combo, so I got the adapter, shaft sleeve (10 spline) and shifter for under $200. That way is probably cheaper than getting all the parts you need. You'll also want an NP205 crossmember and be prepared to drill your frame for those bolts, about 2" in front of your current crossmember holes.
Adam