I think he's got a leak at the joint between the top and bottom halves of the rear cam bearing. This is a metal to metal join without a gasket, and the FSM says to put a light smear of rtv on the mating surfaces. DON'T get it into the oil passage, and use a LIGHT smear, or torquing it down will pooch it into the passage. Ditto the RTV at the right angle turns at the rear of the vavle cover gasket where it jumps over the rear cam bearing.

You can pull the rockers/rocker rails/upper cam bearings without pulling the head or the cam sprocket or cam. Use rubber glove fingers or finger cotts to hold the HLA's in the end of the rockers.