Anyone else ever noticed how much louder valve noise is (or seems to be) when the heat shield is removed from the stock header? I took mine off a while back to clean the header up and left it off. Put in back in this evening after polishing it and my engine seems to make a lot less mechanical racket than before. I know thin wall headers amplify valve noise but I didn't think the stock header was that bad. I guess the heat shield also acts as a sound deadener...