Tap, Tap, Tap...

how many miles on this motor ?? or cam and lifters?? or srpings or push rods,,

maybe a lifter isnt pumping up,,,maybe a worn push rod,,you can buy an additive to stop the lifter from ticking ,,if thats the problem,,,if it works its just a bandaid,,,sooner or later the problem may come back,,

take a valve cover off and look around,,,ide hate to think its a cam going bad,, geting proper oil to the heads?? does it go away when driving ??