The most noticeable advantage of the PCV system is approximately double mileage between rebuilds. A clean air intake for the crankcase vent system keeps dust out of the oil and gives a noticeable reduction of abrasive wear to piston rings and bearings. It won't fix a worn out engine, but if positive ventilation is incorporated into an overhaul, the next one will be a long time coming. I was involved in hundreds of PCV conversions of California cars in the mid-1970's when it became a requirement for registration of pre-1968 vehicles.
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!