That heater is actually for a 48-50 Ford truck. It's the Fresh Aire model. The truck had a duct under the right fender, that air came in. The blower motor was under the fender, bolted to the side. THere's a flexible duct that connects from the side panel to the right side of the heater case. THere's 3 cables in a bracket on the dash that go to the top of the case. I have one in my 50 F-1 truck.
Barry
50 F-1