I'm planning on using the original 6 volt heater which has 2 motors. One for the floor and 1 for the defrost. This is in my '48 chev p/u truck which I've changed to 12 volt. This heater came with the truck. It has the metal plate on the front that says GMC Master. I've never seen this type before. My question is ...... where can I get 12 volt fan motors that will fit this heater ? The defroster motor is a bit smaller than the heater motor. No room for modifications on the housings. Has anyone ever seen this type of heater before and if so, what have you done for 12 volt motors ?