I'm working on my '47 3100 that was my wife's Grandfather's truck. The truck has a Harrison H-01-46 heater that appears to be the original. This is the Deluxe model using two motors, one for the heat and one for the defrost. I'm going to convert the electrical system to 12 volts and will replace the motors. I thought this would be an easy task but have yet to come up with anything that fits. I've searched this site and spent a lot of time on the internet and can't find what I'm looking for. Several people have used the VDO 354 in their fresh air heaters. The problem I have is this motor is 3" in diameter and the center of the heater core is 2 7/8" at best. Has anyone overcome this problem? Is there a 12 volt equivalent to the 6 volt motors I have?