Vacuum diagram for '73 Scamp

The diagrams "in bits and pieces" are in the service manual, in the AC section, and the emissions section. You can download a 73 factory manual here, fer free:

http://www.forabodiesonly.com/mopar/showthread.php?p=1970088617

There should not be much in the way of vacuum "fittings" through the firewall for the AC, only one or two, one of which would be for the water control valve. The other would come off the engine, go to the vacuum tank, and through the firewall to supply vacuum TO the dash control