I did add Classic Air years ago before I but the project to the side. The heater box is lighter BUT with the 134 compressor and other parts it's heavier but at my old age I want air. Years ago I 7/8 Hooker comps and only thin carpet for weight savings and I melted a pair of tennis shoes so I installed 2 layers of insulation in the front. I also found year ago a 4 door Satellite that was a factory air car so I have all duct work and dash vents with controls. Now that was a nice score.
When I was building the car for a hot street car I had a bunch of C body power window mechanisms. All you have to to do to make B body power windows from that is take the b body window arm off the half moon gear and put it on the C body half moon gear and it just bolts in place. I have to change over the drivers side so when I do that I will take some pics. The pass side is done and in. I may pull it so I can lighten them up. I need to pull more weight from this porker. I'm working on that now.