swaping ac unit. Help!

The pre 73 a/c systems have their issues. The push button controllers were a common failure. The hot water control valve is a odd creater too. Rather than have a pring return servo with a single vacuum line, it has 2 vacuum lines on a neutral servo.
The cntroller must vent one as supplies the other. Someone probably has figured out how to replace a leaky valve with a conventional single source n/o or n/c valve and what to do with the extra vacuum line. I haven't had to address that problem yet.
Good luck with it