The more I read on these it looks like Marmon-Herrington converted a lot of vehicles to all wheel drive during ww2, including fords. What you have there is quite possibly a rare ww2 surviver probably worth a lot to a pure collector. here is more info on the Marmon company
http://marmon-herrington.webs.com/truck.html
and here is a website of a guy supposedly the expert on these trucks, per the ford forum( Marmon Herrington Ford F1 - Ford Truck Enthusiasts Forums )
Chucks Trucks LLC., Chuck's Trucks, Chucks Trucks