Engine builders/Gurus, I need your help.

a couple of ideas to check look at the inside of the valve cover to see if the rocker is tapping the cover.ive seen this happen.also seeif the rocker shafts are on the properly as they can be switched side to side and flipped upside down and i believe can impede the flow of oil to the head

if a vale cover problem you can get a set of gaskets that are thicker.

just throwing a few ideas out there for ya