With the engine cool, reach behind the head and use your finger to feel at the bottom edge of the valve cover. Your finger SHOULD NOT be able to penetrate anywhere. If it can, then you are missing the half moon gasket that someone else mentioned up above. Also, feel along the back side of the head and ensure that the round plug is in place right in the middle of the back face.

These two things will cause your top end to PUKE oil like you are dedscribing. You are probably seeing where the oil is running along the edge and down the block.

I hope this helps you find your problem...