If you can find an old valve cover, cut the top, bolt it back on and fire it up. This will allow you to do a visual on the valve train without oil flinging all over the place. If nothing is found, swap valve covers and inspect the other side. Make sure there is already some heat in the motor, so that you can maintain a low idle speed.
If you do this you can press on the adjuster end of
the rocker(use gloves) and see if the sound changes..
also... look at the inside of the valve cover.. make
sure the rockers arent hitting the baffles.. this really
amplifies any noise
