Wait a minute. Why do you say it is sealed like a drum and the intake was probably never sucking oil? I thought you said in another thread the intake gaskets were oil soaked at the bottom. What are you seeing now? Provided you've pulled the intake again, are you seeing an imprint in the gasket from the manifold 360 degrees around the intake port or not?
This still looks like an intake manifold sealing problem to me. You are either seeing an imprint in the gasket and oil soaking of that gasket or you are not. When I had this problem, it looked identical to what you see. I saw oil above the intake valve inside the port just as you do. When I corrected the intake interference at the china rails and used an adhesive around the intake port gasket area, the problem was gone.
