Heater core plumbing

[ImNoSpaz]

I'm probably confusing myself by over thinking.

I have the 7.4 Vortec in the 67 with the reverse water pump. I'm doing the a/c and heater plumbing and am stumping myself on the heater valve. We put the 69? heater control in because it is vac control for the heater, and we didn't want the additional cable.

The water pump has no out/inlet port as others. It has the pad for a nipple or fitting but no threaded hole, but the radiator has a port just below the fill neck.

Here's where I get stuck. If I put the vac heater valve on the small heater core tube and then run it to the radiator, will it work? It will stop flow when A/C is on, but the heater core is still hot. If I put the valve on the larger core tube, it will stop flow (this hose goes to intake manifold) but the core will still be hot...right?

I assume the reverse water pump is just reverse as far as the blades turn, but does not effect the actual direction of flow, right?

I have done a whole lot of things both custom and resto, but have never even thought about heater plumbing other than 1 hose goes to the water pump and the other goes to the intake manifold. My bad and my head is hanging low right now.