I rebuilt an NA engine a couple of years ago and when I put it in I plugged the PCV holes in the exhaust valve cover and just vented straight out the holes in the intake valve covers. Pulled it out earlier this year with 38K miles on it to install TT engine. I pulled one of the valve covers to see if any sludge had built up and I think it was actually cleaner than when I put it together. Current TT engine is set up the same way. I even did an oil analysis at one point and it came back great.