hello my 98 300ex is making a metallic noise, it sounds like pinging. it is coming from up top. it happens when it has load in an upper gear. it has a new piston,guides and timing chain. when i had the motor apart, the rockers were getting flat. i am hoping this is my noise. the valves are adjusted to .004. it has a k&n jet kit and filter,and a cobra exhaust. it is not running lean because when cold it has black smoke when revved. anybody have this sort of problem.

 

YES IT WILL.......Just replaced a set for a friend a couple weeks ago on a 300ex. Cam was done too!

 

yeah i am sure i will need a new cam, sometimes when it started to tap at acceleration, i can feel the power drop and it would stop for a second and the power came back.