Ignore the advice about using a freeze plug in the road draft tube hole unless you own a lot of stock in an oil company. The factory original PCV valve was in a standpipe at approximately the height of the lip of the valve cover to prevent splashed oil from being drawn into the valve and burned by the engine. Use an oil filler cap with a vent to admit fresh air into the engine for ventilation if you choose not to use the factory method of plumbing air from the "clean" side of the air filter into the rear of the valve cover near the back of the driver's side. That system was used on delivery trucks, step vans like bread trucks, and others which seldom got up to 30 MPH where the road draft starts to work properly.
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!