obviously a PCV won't work under boost, but on a street car, you're only under boost at WOT, and at part throttle cruise w/ manifold under vacuum 98% of the time.

if you have a breather on one side, that would allow pressure to breathe out under an extended WOT pull, but the PCV would open up as soon as you lift and go into vacuum on the manifold.

I'm just starting to learn about boost as I help a buddy put together a forged 5.9L to toss a turbo on in his Dakota....I know that boosted motors need a larger ring gap than NA, but if you're getting so much pressure that it can't breath out of a breather filter plug in the valve cover and starts pushing out gaskets and seals...wouldn't that mean you have too MUCH ring gap/blow by?