Why are you going about this the hard (expensive) way? If I were you, I would simply change out the input gear on the transfer case. There are several members here (me included) who have extra 10 spline NP205 input gears, and would probably trade for your 27 spline input gear. The 10 spline coupler is/was a production item and is still available from a variety of places;
Northwest Fab comes to mind first. You're in Maine, PM "MEK5", I'm sure he can help you if he has time.
Jimbo