The Stovebolt Site Forums The Shop Area Engine Shop 47-55 1st, Are there 2 types of breather pipes ?

I was told that on a PCV system adapted to a ..54 truck that there had to be some type of air flow thru the engine. Because of the vacuum that is generated from the carb. i.e., from the carb, to a PCV on the oil cap and breather tube open. Or carb to PCV on breather tube and vented oil cap.

Or have I been misled.