As long as the idle doesnt speed up any on warm up sounds about right, but as a motor warms up and usually gain a couple hundy. Sounds great out the exhaust! I think my vavle train is a little noisy but sounds like you have oner or two really putt'n out some clatter. I would check for contact on valve cover or pushrod through the head clearance and since you already checked lash and took that out of the question. Posssibly a loose piston clearance on forged pistons? Does the clatter get better after it warms up?