Sorry...truck is a '53 3100, my present heater is a Harrison, needs everything, so I'm going aftermarket.
Another option, depending on what Harrison heater you have is to replace the core and fan with a unit from Brassworks, as long as they are still offering it. Here is an old thread that I posted about re-doing mine.
https://www.stovebolt.com/ubbthreads/ubbthreads.php/topics/1011570/Re:_Brassworks_Recirculating_H.html#Post1011570
