A/C Question? After Market System

The two main brands of modern AC systems are just like your stock system - heater and AC all in one unit. There used to be add on units that were separate from the heater on heater only cars, but they are real dinosaurs. When you say "I tore out the whole AC system", do you mean all the stuff under the hood, or under the dash too (which would remove your heater too)? If the stuff is still under the dash, you can continue to use the heater part of the system until you are ready to do something about it. I've been driving one 70 Dart since 1978 using the heater without any of the underhood AC stuff and it works fine.