It's been a while since I've had a second-generation six apart, and the weather is too raw to go out to the shed and pull a valve cover today, but I seem to remember sort of a baffle near the midpoint of the cover that routes incoming air toward the crankcase, and helps the PCV valve create a down/up air circulation. Like the old country song says, "I've been wrong before", so don't take that as gospel. The older systems with the road draft tube did the same thing by creating low pressure at the end of the tube above 30 MPH, and drawing air into the valve cover with slots or other venting methods.
Jerry
