ac evaporator

Back when these cars were new A/C was a $400 option on a $3300 car, so it was a fair percentage of the car price. For this Chrysler did dive you something for your money and the components used were nicely overdesigned. The RV series compressors were some of the most rugged ever put in a car and the evaporators and condensers were real copper and brass of a decent thickness. Unlike new cars where evaporator problems are fairly common the old stuff almost never failed.

I would have no problem using an original evaporator if it were in good physical condition. If you compare it to the newer aluminum/plastic stuff made today you'll see what I mean about the quality level of the older stuff. I'd flush out the original evaporator and use it.

On the condenser, Yes, R-134A is less efficient that the old R-12 and a parallel flow condenser helps transfer heat better to make up for this. And, you want to move as much air through the condenser as you can so a good fan and shroud really help.