On a 1970 455 with a SP1 intake, does it matter where the PCV is hooked up to the intake manifold or the valve cover? The reason I am asking is that I had previously changed over to the SP1 intake and covered up the bottom of the manifold to prevent oil splashing on it. I then proceeded to hook the pcv in the valve cover. I seem to be getting oil pushed/leaks out of the pan and breather at higher rpm. Considering there are spaces for the air to get down below the heads via gaps between the pushrods and hole and the oil return holes I didn't think this method would produce any worse results then running the PCV in the intake. Any thoughts? By the way the breather is now a K&N the open element type.
Try This As with the factory set up, the PCV valve should go directly from a crankcase vent hole (such as the intake manifold on Buicks or the valve cover on Chebbies) to manifold vacuum. Are you sure your valve cover has the hole punched through and that there is sufficient vacuum to the PCV? Is the PCV valve good? If it is a used one, try a brand new one and see if that helps.
