cabs are essentially the same but 1/2 ton frames are very different from 40 to 47, 47 have the ladder type frame and 40/41 have a frame same as a 35-40 car. you would make some sort of adapter to mount the sheetmetal to your frame and drill some holes in the cowl of the 47 to attach the front fenders, you would also have to remove the 47's fender brackets from the cowl and fill the holes.
