I'm not sure if a Dart and a Valiant are the same or not, I have a 66 Valiant with a slant and heat only. I've had the heater control unit out, it is cables only. If yours is similar to mine, be careful when you take the bezel off and give it a shot of lube before breaking the nuts loose. The posts that go through the dash are plastic, I snapped one off because I thought it was metal and the nut was frozen on.
