It is important to cover all of the bases when designing a custom PCV system, especially when drawing vacuum from the draft tube (virtually directly from the crankcase).
More modern PCV systems do not pull directly from the crankcase. They pull from the valve cover. There is a lot of oil splashing around in the crankcase making it a less-than-ideal place from which to draw vacuum.
Another factor to consider is what size orifice to use to prevent too much applied vacuum.
Another factor is to determine when is the ideal time to do the majority of the purging of crankcase contaminants. Modern PCV systems take this into account.
I don't have a PCV system on my Stovebolt engine. I religiously change my oil every 3,000 miles.
Carl


1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission