Why not just use the factory adapter fitting that bolts onto the block in place of the road draft tube and an inline-style PCV valve that plugs into rubber tubing on both ends? I installed hundreds of them at my shop in the Atwater/Merced area in the mid-1970's when California mandated that all vehicles had to be retro-fitted for "closed" PCV systems.
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!