How to run Heater after A/C deleted

Pic above is a later model. The roundish black plastic thingy near the valve is the vacuum reservoir. Notice that this model has much smaller vacuum servo on the water valve with only one hose attached.
I've often wondered if the big *** 2 hose servo on earlier valve didn't also serve as a reservoir of sorts. Since I don't know, that's why I stated above that deleting that valve and servo may bring about the need for a reservoir.
If the blend door positions do change under low vacuum conditions, it is just a momentary nuisance.