I don’t have time to read all of that article right now, they make a mistake pretty early. They say the 440 used a “closed” PCV system and I don’t believe that to be correct. Every OE PCV system I’ve seen is an open system that brings in fresh air to the valve cover and pulls it through the crankcase and back into the engine to be burned. In that case, there is no way for that system to develop any vacuum in the crankcase.
