Lot's of hard work but well worth the effort
I did that to a 71 Chevy 8-9 years back. Converted a 2wd into a 4wd.
Bought a 4wd frame, front axle, T-case, and swapped everything thing else over to the 4x4 frame.
Neighbors thought I was nut's too, especially when I finished up Sunday night, and cut up the old 4x2 frame with a torch after dark. Nothing like sparklers in October.
Keep up the good work.