You can find metric and US standard ends of all types at AC hose sites. Speedway has some, so does Vintage Air. Here's a good site (I haven't used them though):Automotive Air Conditioning A/C Hose Fittings
The newer GM stuff will have metric threads also, I'd say from 1980 on for sure. You can swap the metal tubes for rubber, or silver solder new metal tubes. You'll just have to figure out what threads and sizes you have and make hoses to fit. I had to do that on mine -- I'm using the original 1963 evaporator and expansion valve (under dash parts) with a late 90s Chrysler LS parallel flow condenser (in front of radiator) and a 1988 Jeep Sanden compressor. The Chrysler used a metal tube to the drier with a quick connect fitting IIRC, but I cut it and used a compression fitting to mate to a short custom made rubber line to the universal drier. The other connection to the condenser was threaded in. The under dash components used flare fittings, the compressor and all other fittings used new style o-ring fitting. Had to have all hoses made. Good luck!!