Do we tave an air conditionning unit that would replace the OEM unit on a 1968?
I don't think I can repair the original unit as several parts are missing...

 

you can replace a missing or non‑repairable OEM air conditioning unit on a 1968 car with a modern aftermarket system instead of trying to fix whatever is left of the original. There are companies like Classic Auto Air and Vintage Air that make complete retrofit A/C kits engineered to fit classic vehicles, including ’68 models for pretty much every classic line (Chevelle, Camaro, Mustang, Firebird, etc.). These kits include a new evaporator, condenser, compressor, hoses and controls designed to fit your car with minimal modification and will give you modern cooling performance. They often use fully electronic controls and simplified wiring so you don’t have to source individual parts yourself. There are also universal under‑dash or custom kits https://tropical-casino.com/ if you want something that works in a variety of cars rather than model‑specific gear

 

OP, you really don't want to restore the original AC, just put in the Vintage Air system. You lose that big brick of stuff on the firewall as the Vintage unit comes with a new firewall block off plate as its a complete contained system inside your dash

 

I need to find one for my 68
I'd love to find a factory R12 system and fix it
I believe all the parts are still available
And
I am sitting on 15 lbs. of R12
Make that 40 lbs.