A/C:
Yes, Cadillac had it by 1950 also. I think Thermador in California made a side window mounted one also.
Kaiser Frazier was in Willow Run Michigan, and also made the Henry J car, which Sears sold for a while as the Allsate car.
Willy's Overland owned Jeep before AMC, so some are confused by that.
Nash and Hudson merged to become AMC, they came out with Rambler.
Kaiser and Willy's were affiliated then merged with Frazier before liquidating.
GM bought the Willow Run plant in 1954 when their Livonia Hydramatic plant burned to the ground. They added an assembly plant in 1960 to make Corvair's, then the Chevy II. The final product was the 1991 Chevrolet Caprice.
The Hydramatic facility closed last decade.
Toledo Ohio Hydramatic, and Punch Powerglide in Strasbourg France make the 650 LE automatics. Strasbourg also builds the ZF HP 850, as it is no longer owned by GM.