Working on deleting air on my 73 cutlass. I bought a non AC blower box from a 74 thinking it would work, but no joy. Now looking at the AC delete box from AGM Industries. Anyone have experience with these? Also not sure about the heater resistor (mounts in box) use the original four wire one or use the three wire one off the 74. There is no provision for a vented fan motor on the AGM box so I guess I would have to use the non vented fan motor like on the 74. Any advice would be appreciated.

 

Welcome. As you found out, the firewall cutouts for heater-only cars are completely different from those of A/C cars. In addition, the underdash part of the box for non-A/C is also completely different. Assuming you want to retain heater and defroster, you must either use the aftermarket "A/C delete" box with your current underdash unit and controls, or you must change both halves of the system and control head as well as welding up the larger holes in the firewall. Keep in mind that the underdash part of your A/C system uses vacuum to actuate the flapper doors, so you still need the vacuum ball and connections to the engine. Yes, you can use the non-vented fan motor.

 

Thanks Joe, I ordered the ac delete box and will use the non-vented fan motor. Do you mean the vacuum ball that sits on the right side inner fender well? Sorry for the silly questions but the car has been torn apart for quite some time.