pcv valves will suck oil water B.S and re burn it in the engine. two free breather may pull some oil cheap ones more then some of the better open breather that are baffled helps this . on hi CR engines i do not care for PCV on any thing street or race .i do not care to reburn bull shit if you have a big cam the pcv may not work anyways pcv is not better it just hides the wast by reburning it and that can not be good for the engine