71 Dart A/C car heater issues

My 71 swinger is a factory ac car, however the components in the engine bay have been removed. I dont plan to put AC back on the car, but im having issues with the heater. When you push the "max ac" or "ac" buttons the fan works great, but does not blow warm air. When you push "heat" or "def" the fan hardly blows at all. The car is a driver and my goal here is to have the defrost and heat blow strong, would be nice to have the heat blow out of the under dash "ac vent". It does also have a valve in the heater hose in the engine bay hooked to what looks like a small vacuum pump that is hooked to the manifold. Any help, or point me in the right direction would appreciated, thanks!

You can see the valve in this pic on the leftIMG_17291(1).jpg