To properly vent a crankcase there needs to be a one way valve otherwise you will suck almost just as much back in as you are pushing out.
On the Predators (the hemi at least) and similar they all already have a PCV built in from the factory. As ThunderKart said, the air moves both out and in, that's what powers pulse pumps.
The factory PCV is on the underside of the valve cover. It's a reed-type valve in a flat brass body, and it opens and closes with every up/down stroke of the piston, exhausting out the fat (3/8" ID ?) black tube right into the airbox. Even a governed one can flap that reed 3,600 times per minute. Or would that be 7,200 times?
So if using that tube's outlet to run a pulse pump, it doesn't work worth spit because it's all one-way exhausted air. On the hemi, facing the valve cover so OHV is right side up, the reed valve occupies about 2/3 of the right hand underside of the valve cover. Any tap you make for more relief must be in the left hand 1/3 space. OP was concerned about getting a NPT fitting into the valve cover, he must have a non-hemi with the very thin stamped steel cover, too thin for NPT. The hemi cover is cast, plenty of metal, so NPT seals perfectly.
A regular V8 motor's good-ole-days PCV valve with the ball bearing in it would never open up on a small engine, there's not enough crankcase air displacement to push that heavy steel ball.