I have a 427 FE with 2x4 tunnel wedge intake manifold. I see a need for a change in my crankcase ventilation system. I currently have the usual baffeled
oil filler tube in the right front of the intake manifold with the usual push on breather, and a cast alluminum breather stack at rear center of the intake manifold. The 2 valve covers are the cast alluminum Lemans valve covers. Each valve cover has a grommet that converts the twist in hole to a small hole for a PCV valve. There is a 90° PCV valve in each valve cover. I have purchased a chrome Motorcraft EC-2 breather cap which I had planned on replacing the grommet and valve in the rear of the right valve cover and routeing the flow through a 3/8 hose to a fitting on the other side of the intake plenum that would have manifold vacuum. The engine sits pretty much level so the intake tilts the carbs lower infront. There is not much more height clearence on the front of the left valve cover. I was just told by someone that I need to do away with the most of the breathers so as to actually pull a vacuum on the crankcase. I was preparing to remove the grommet and PCV valve in the forward portion of the left valve cover and replace it with a twist in breather cap ,but may now change the PCV valve with an 3/8" elbow. Please, I need some more input . What did you do ? what worked for you?