Hevyhauler makes some valid points, but don't overlook the fact that you'd have to somehow make the duramax run independent of its native truck and associated computers. That to me would as daunting as the mechanical aspects.
I'm not saing it can't be done, but you might be better off buying the '01 and using it on the farm, and fixing the '41 and drive it around town.
Scott


1947, 1950, & 1952 Chevrolet 1/2 ton
1952 GMC 450 series Cab Over Engine
1946 Chevrolet 2 Ton