I have checked my valves which are in spec but it always ticks. I am planning to buy the new tappet adjusting screws just in case they are worn. The other day I did the old trick of putting the screwdriver against the valve cover and the handle to your ear, it works kind of like a stethoscope. The odd thing is that on the valve covers you can hear no ticking. When I touched it to the exhaust pipe it was ticking away. No exhaust leaks. So, is this normal noise which is heard through the thin header pipe since they don't use the thick cast iron like factory cars?