Chipmunk, Try Hemmings magazine for a vendor there are several in this months issue that specialize in electric wipers, or you may find one in a GM car or truck that will work at the salvage yard, if you are running 6 volts you don't have much choice but a 12 volt unit sometimes will work, just real slow. or go to the Filling Station, Jim Carter truck parts, American Classic truck parts, Chevys of the 40's, blah, blah so on....I have seen them from $150 to $185
I am going to move this topic over to Trucks tomorrow, maybe it will get more hits. MrMack