You can get the whole thing new from this Vendor:
http://www.classicparts.com/1947-54-Heater-Defroster-Assembly/productinfo/68-991A/#.VGZxqvldVmM
Not the recirculating one but a replica of one common to your truck. About 200.00 for a complete heater. With ducts as well. Or you could try the Parts Wanted section and see what is out there.


Steve H