valvetrain noise 5.9 magnum

Hard to diagnose from a CPU,but first thing I must say is DO NOT rev that thing over 5500 rpm with stock valve springs!!! 2- there is NEVER valve lash with any hyd cam! Preload is what you want and with all stock parts should not be an issue,but it's easy to check. The factory cams can degrade and depending on how bad can have wear on the base circle(but pretty rare,unless you've been running that thing to 6500rpm for a while,LOL)that MAY be an issue,but I'd doubt that. What oil weight are you using? Have you recently changed to a heavier oil?