Hmmm. Could this be the reason why GM does not have an intercooler as an option?
It would disable the PCV system and put them out of emissions compliance.
I remember back in 1999 they toyed with the idea in a pre production SC & intercooled Buick Regal but it never made production.
So, if I understand correctly, adding a breather to the front valve cover is OK for a supercharged or turbo L67 but not OK for a NA 3800.
Sealed or vented, it makes absolutely no difference to the idle speed on my engine.
Purely cosmetic.....until I get an intercooler.