Father-Son 1974 Duster Project

I got a complete heat-AC box from another member. Here it's pictured with the side that bolts to the firewall. The opening where the fan and condensate drain were was cut away with a grinder for some reason. Above the complete box is an un damaged version of the same part that was original to our car.
I need to find a rebuild kit for this box and also need to pressure test the heater core and AC coil
Can anyone tell me where and how I can get fittings to test the AC coil or should I just cobble some rubber plumbing fittings to get some air pressure on these things?

View attachment image-2143278127.jpg