The PCV system was designed to work off of manifold vacuum..In other words below the throttle plates...Theres not enough vacuum above the plates (air cleaner) to operate the valve....What works best is a breather in one valve cover and a PCV in the other...At idle the PCV is closed and the breather which is piped directly to the air cleaner is pulling any blowby back into the engine..As speed increases the PCV opens and gets full circulation through the crankcase via the breather/air cleaner......If you don't want to tap into the intake..then a straight breather would be best...Depends I suppose on where you live (emission tests etc)...how new your engine is etc...