sanded down the pitting on the tappets then polished them, inspected the rocker shafts for play, re-installed the valve cover, adjust valves/tappet clearances, rode the living piss out of it for 20 miles or so. It seemed to like the abuse. I think it is possible I had a few clearances too tight prior to this endevour. The tapping noise is more consistent with all valves now, gets quieter when hot, and is not heard over the exhaust over 2,000 RPM.