Re: Oil in the upper intake
Yes, its a vacuum source. Flow path is in through filter in the air box (my '94 has a separate PCV fresh-air filter under the main air filter), through the fresh-air hose to the left valve cover, through engine picking up blow-by gases from the crankcase (and picking up a bit of oil from the right rockers!), then out through hose & PCV valve to intake. Since you saw the baffle, I guess that's just the way it is. I haven't taken the upper intake off the 351 (yet!), but when I do I'll probably find just what you did.
I was wondering... when you took your valve covers off, did they have cork valve covers with little bits of metal rod (2 under each bolt-head area) pressed into the gasket? I worked on a '90 302, and it was one of the dumbest ideas I ever saw. The pieces of metal helped stop the gasket from being compressed too far under the bolt heads. Old gasket, lots of little pieces of metal coming loose, in an open valve train area. When I realized it, I counted them all. I was short 2 of them. Uh-oh. Looked everywhere around the valves, intake, etc. finally found one on the floor. One still missing, presumed down to the crankcase. Oh good! But found it on the floor later in cleaning up! What a dumb idea!