I bought a vintage air kit from the US (Ebay ID 1329Keith) Got the kit about a year ago shipping made me nervous, but ebay shipped themselves and in total I saved about $800 getting it this way. Fitted it all myself save for the hose crimping (hoses and fittings included, just not crimped up) and gassing / leak testing. Only parst I had to buy was a 47" v belt and double row engine pulleys (I don't have P/S).
I'm no mechanic, but the instructions are brilliant. Heater / AC unit all in one, polished compressor ($60USD option!), uses original heater controls with electronic mod. Total cost about $1600 delivered maybe more now due to dollar.
Just make sure you're only using the smaller steel fan original fan shroud if you're running a 4 core, I had to cut my fibreglass one down to clear the compressor, looks a bit crud.