66 Dart Heater Cable Question

My 66 Dart 270 Slant 6 non/ac had a single sliding lever for heat. Top lever is Heat/Defrost Bottom is Temp/Warm. I purchased a stock 2 lever model and notices it has 3 cables and the heater has vacuum diaphragms. Can I take off the Diaphragms and just have the cable regulated controls? I don't know if this dart had push button controls or not. IMG_0894.JPG