The Stovebolt Site Forums The Shop Area General Truck Talk How do I knw if i have Deluxe or Standard heater?

I'm not sure about GMC's, but in Chevy's the deluxe heater is the 3 or 4 lever one, and the thiftmaster heater has one pull/twist knob that is mounted in the same location as the 3 or 4 lever panel.

IIRC, the 4 lever one is for 60-63 and the 3 lever one is for 64-66 and the one knob thriftmaster is for 60-66. Personally, I have never seen a 2 lever heater in a 60-66 truck.