Whats the story with this Aftermarket A/C unit??

Anyone know the history of these A/C units??

Says "Sears" on the face, found a sears receipt from 1971, not 100% sure it is connected with this.

Bought the car from the original owner and he says the A/c was added shortly after the car was new (car is a 68 ) because he wasn't going to pay the "outrageous" price for the factory installed setup.

I bet Mr. Del (67dart273) knows what this is