valvetrain noise 5.9 magnum

I'm hoping its a rocker or valve or something on the heads wich I am about 80 percent sure it is because I can deffanatly hear it on the top of the engine. I have been thinking about getting some new heads anyways but didn't plan on having to do real soon. Thinking maybe I could pop the valve covers off and make sure ll the bolts are torqued to 25 ft lbs, that's the only thing I can think of doing. Maybe try running some kind of cleaner thru the oil system, like marvel mystery oil or something?
This engine has had synthetic oil ran thru it all its life since break inn and the oil has been changed every 5 to 7 thousand miles with a wix filter and Valvoline synpower 10w-30 oil all its life, so its been taken care of, never has been neglected, but it has been ran pretty hard a few times but nothing extremely wild because its always been in a 4x4 truck.