Does anyone know if you can add an entire A/C system to a '73 240Z that came from the factory without? I am contemplating this matter considering how warm it has been this summer but just don't know if it's possible. Any responses would be appreciated!

Motorsport Auto has a complete kit to put A/C in. It's a bit expensive, but not bad considering what you get. No more 2 windows open at 60mph.

It also has an upgraded rotary compressor which will work much better than the original style compressor.