Need help perfecting the budget build hemi swap

My 71 Cuda had a valve in the #4 position that was cable operated. But, I thought it had a cross over also. So the water reached that valve, and if it was activated it turned the water back toward the engine at the valve. This 75 duster doesn't crossover. It seems to have sort of a diaphragm that expands, and contracts with heat ( I think ) and a vacuum hose from the valve to the firewall.
In your last PM, You were telling me about vacuum operated flip up head lamps. My friend Artie has a 58 VW bug, and ( I could be wrong ) I think the window wash is hook the the valve on the spare tire, under that front thing that VW's have that isn't a hood, because there's no engine in there.