Kaiser-Frazer, like other car companies of the time had the heater/defroster units set up as dealer install items for most models. If a retail customer was coming to the factory to pick-up their car and a h/d was desired, the dealer could specify that the factory install it for delivery & it would go in at the Courtesy Garage before pick-up. Of course, the kit and install labor were extra cost. 1951-54 Early special Kaisers used the same unit, which had the core in a black box on the engine compartment firewall, with inlet and outlet water hoses going to points on the engine. There was also a large blower unit with cage fan that the right side air duct flowed through (the vent port on the passenger side in the interior had a baffle with a lever so you could run the air through the heater or direct out of the vent into the interior). The 1947-48 model year cars did say "air conditioner" because the air duct had venturi's in them which sped up air flow naturally and in the process created condensation and drain off of some moisture. The air coming out of the venturi was considered "conditioned. A 1951 Nash TV commercial shows a diagram of how their version--The Nash Weather Eye System--works.
Ford was selling cars to dealers without heater/defroster units into the late 1960's. I remember looking at some 1967's on a Ford dealer's lot in Key West FL with my father on our last trip down to Florida; some had no options listed and did not have the h/d units.
Now, they are manditory along with air conditioning for the most part in order to make meeting EPA emissions easier (one model year it was found that Cadillacs would not pass with the a/c turned off).
