Tap, Tap, Tap...

Hi-
I hear a tapping from my 1968 340 motor.
Spead of tapping increases when revved.
Motor runs smooth, no smoke, etc.
My mechanic thinks it is a stuck lifter.
I changed oil (VR-1, OEM Mopar filter) in spring and noticed
that oil reads past full level on dipstick.
Could this be problem?

Thanks, Rick