The best way to create good circulation of air through the entire engine is to draw air out of the former road draft tube position with the PCV valve, and input air into the valve cover by plumbing air from the filtered side of the air cleaner. That introduces air into the valve cover, draws it down through the pushrod cover, and completes the circuit by sucking up whatever blowby gases are present around the crankshaft and rods. All the gases and vapors are then drawn through the PCV valve into the intake manifold and burned along with the fuel mixture. It's a totally clean setup that does not allow any dust or dirt to get ingested into the crankcase. Later-model engines use a hose from the small separate filter unit in the side of the air cleaner housing to supply the air to the valve cover. Either method supplies clean air for crankcase ventilation.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
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