The Stovebolt Site Forums The Shop Area Engine Shop 235 six with "tapping, pinging" noise?

I would think rod bearing noises are a thunk sound that you'd be able to recognize as the sound is deeper within the block.
A tapping sound to me, points to slack in rocker arm activity (lack of oil, excessive slack).
If exhaust, your ear should locate the sound to that side of the engine... if lifter/push rod, to the top.
If it were me, I'd first pull the valve cover and investigtate the action... and go from there.
Jerry