Have you ever thought about retrofitting factory AC into your 65 GS? All the correct parts are hard to find, but we have a complete system available removed from a 65 GS parts car and in used, as-is condition.
System is truly complete, including all interior vents, controls and air box needed. For the engine bay, includes compressor, all brackets, muffler, dryer, all lines and other components located under the hood as well as the correct pulleys and vacuum check valve for the engine. Blower box, condenser, evaporator, POA valve and fan shroud included. The fan shroud is original, not a reproduction. It has a repair on its bottom side that is not visible except from under the car.
You're not likely to find a more complete system available anywhere. $2,000 for it all.
A list of included parts and pictures are available. PM if interested.

Chuck