5.9 Magnum valve train sound

I just put together my 5.9L Magnum with new heads and used the stock rocker arms with stock springs. I torqued the rocker arm bolts down to 21ft-lbs or as close as i could on my torque wrench. My issue or issues is that when the engine heats up and i shut if off, you hear pinging noises.... Now i've allowed this thing to heat up and cool down a few times to let everything settle and i still get the ping/pop sounds when i shut it off. Also i can hear the rockers clicking after if warms up and over idle rpm around 1500rpm +.

Is the ping/pop noises from loose or even over tightened rocker arms? wrong grade of oil (Running 10w-30)?

Any ideas on what to try or do?