STEVEOLBOY --
Hi & Welcome. I've got a '46 6400, all stock (235, 4 sp with 2 sp vacuum rear.) The GVWR is 17,000. I've never put near that much on her but I'm sure she'd move it OK, albeit slowly by today's standards. Trouble is stopping -- even with up to original spec brakes don't expect this vintage of truck to stop like a modern one equipped with disc brakes and radial tires.
Just my opinion of course, but I say go ahead and use your antique truck as heavily as you like (within its weight rating and in good repair of course) but be prepared for it to act like the old truck it is.
Good luck
Pete P.
Harborcreek, Penna.
