I am trying to contact the guy with this truck.
After some Internet sluething and then simply calling numbers until I found him, I managed to find the guy who owns the 1-ton I've seen on the road running an IFS.
Today I spent almost three hours chatting with him about the swap, asking questions and hearing stories. He is a retired guy who has run the truck all over the US. It is an '85 3/4-ton IFS and when I'm not sitting in a hotel room I'll post some pictures and describe how he did it and what he thinks made it a success.