I ran a shop in California in the middle to late 1970's, and we retrofitted several vehicles to closed-loop PCV systems. It was a requirement enforced by the local DMV that no open-crankcase systems were allowed to be registered when ownership changed. The vehicle also had to pass a visual inspection and an exhaust emissions test, performed by a state-licensed shop. Fresh air was drawn from the "clean" side of the air cleaner by installing a vent tube from the air cleaner to the valve cover, and a PCV valve was installed in place of the road draft tube. Any vents, such as valve cover slots or vented filler caps had to be disabled.
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
Love your enemies and drive 'em nuts!