I'll embarrass myself then. I spent a lot of time and effort rebuilding the heater. I changed the heater motor to 12v, repainted the entire unit with hammer-tone paint I got from 'bolter truckernix. Had the decals from Carter's, which didn't seem to be correct. All this was done as the truck was in another shop being sanded and painted, replacing rotted sections. We even replaced the firewall. After the truck was mostly back together, I wanted to install the heater but the two heater hose holes in the firewall were quite different than the heater required. Turns out my heater that was in my truck was incorrect, from a '48 car.
