My 72 has factory a/c that most likely needs a charge for starters. The whole system in general is really weak, the reason I say that is that everything seems to function like it should. I can change through max, norm, vent, def, ect and can physically hear the system making changes, the engine RPM's drop when going through the a/c modes. But barely any sort of air comes from the vents in any mode. The blower motor sounds like its ok so I dont think that its just weak but it wouldnt hurt to swap it out for as cheap as they are. I pulled the dash and had a look, I used some heat tape to wrap up some of the duct work where i thought there might be some air leakage going on, but it didnt seem to help much. Do these trucks have any sort of cabin filter? Im almost tempted to pull the trigger on a vintage air but I cant see spending all that money on all that nice stuff with the rest of the truck being mostly original. The triple digits are coming in Texas so I need to "get hot" on this issue. Does anyone have any suggestions on a few things to look into that might be weakening the system?