No worries about questions--i am by no means an expert ,but after some recent PCV woes i leaned quite a bit.
The PCV is meant to maintain equilibrium between the intake and the crankcase and return unburnt fuel vapor to the intake to be reburnt. It serves as an early emissions reducer, gas mileage enhancement and also to keep the corrosive vapors out of the engine. It is really only supposed to open one way when there is a pressure imbalance when the crankcase pressure is too high it bleeds it off.
When doing PCV retrofits just make sure you get the right valve direction depending on if you are fitting the valve in the valley cover or the manifold port. The wrong one will result in a vacuum leak. Or a malfunctioning or stuck valve will result in a vacuum leak as well.
Mike Rizzo
1963 F100 "Rudy"
Daniel Island, SC