66 valiant a/c and heater vacuum valve

I don't know of a vacuum "pump" on the right inner fender. A vacuum operated water cutoff valve had 2 vacuum lines and heater hoses attached to it. It stopped hot water from entering the heater core when a/c was in use. If it works, doesn't leak water or vacuum, leave it or delete it. If it's faulty delete it. Heat only builds didn't get such a valve. Water went through heater core at all times.
Some owners have placed a hand operated gate valve in this heater hose line ( even those without a/c ). This to keep the interior a little cooler in summer.