General A/C questions - missing some components

BillGrissom;1970034241]As I recall my 69 Dart, the factory AC had just a thermo-mechanical expansion valve on the firewall. It had a "gas thermometer" that stuck in a well in the tube after the expansion valve, a thin copper tube like you see on older gas water heaters w/ continuous pilot flame. That made pressure for the diaphragm of the expansion valve, making a simple temperature feedback loop - lower temp choked off the refrigerant flow, higher temp flowed more.

I just replaced that expansion valve on my 72. It was $28 at Autozone. Easy install too :)