In dirtbike engines I've heard the phrase "tappy valves are happy valves" but I'm not sure it transfers over to cars. My 06 GT that I've been fixing over the last year is now running and driving with ease and doesn't seem to be lacking power but the loud valve train has me really worried. To the point that I installed a prosport oil pressure gauge. I'm getting 9 or 10 religiously at idle and 59 at 3.5k RPM so I'm well within spec running 10w40 synthetic mobil1. Over the last few months I've done the timing belt, had both heads resurfaced and inspected, replaced 2 rocker arms due to bent valves on #1, set valve lash according to FSM with engine cold. Have not readjusted at hot however but from what I've read, valve lash wouldn't be THAT noisy. Every seal/gasket from the heads up have been replaced. Spark plugs, full tank of 93, all accessory belts. I've done a lot to the car so far without getting into the block so I'm happy with it. It's just that dammed valve chatter.