I know theres a bunch of threads on this because I have read all of them ,, but I want to share this because I would have wanted someone to post this if they had known,, I have a 350 chevy with 60 lbs of oil pressure and I pulled the pcv covers off and put on some edelbrocks without breathers,,, I got so much pressure built up it blew oil out everywhere. Fill tube, dizzy gasket, valve covers, I was gonna do one of the pcv tricks in the threads, when a drag racer friend of mine told me about this,,, You take the edelbrock valve covers to a machine shop and have them mill off the edelbrock script,, have them make it the shape of a rectangle,, then take a set of edelbrock tall breathers,, sold by summit, they look like offys but alot cheaper fit theses breathers to the valvecovers and drill out the holes,, at this time I hand finished the cut off fins on the valve cover to make it look finished,, polished the whole repair and bolted them on,,575 miles so far and 2 trips to the drag strip with at least 15 passes and not a drop,, all I have is these breathers and the fill tube at the front of the manifold,, I know alot of you will preach the positives of a pcv,, but if you just want breathing without leaks,, this works