Well, it looks like my first thought was correct., turns out the noise is a exhaust leak from a partially blown out header gasket on left head. The mechanics I brought out thought valve train at first too. He checked and found left rockers were much tighter then the right. So he adjusted them all and noise was still there. We then tried to locate with stethoscope and piece of hose, found it quickly. Now waiting on new header gaskets from Summit and the world will be right again. Thank you all for the help and tips.
