have small coating of engine oil in a couple of the runners,,,,, removed and inspected lower manifold, no cracks, gaskets looked good,,, so put in NEW lower gaskets, still oil in lower intake,,
Sometimes it still makes its way in there through the valve, and that is why some people install filters or "oil catchers" between the PCV valve and the intake. You could look into doing that. Also, have you modified the baffle on the oil filler neck on the valve cover? It can get into the intake through there too, if the baffle is modified or removed.