hey guys finnaly got my rad in and broke the motor in tonight. everything is great runs a steady 180 or so when warmed up, oil psi good. but while i was breaking it in it seemed to tap from the valve covers in different areas. but only in the upper rpm range. like it doesn t do it at 1800 but it will at like 2300 to 2400 then stop. now it does havbe open headers on it and is kinda very hard to determine whether or not this what it real is (maybe just an echo in the engine bay) so maybe i should put an exhaust on before i go any farther. just wondering what your guys opinions are on this.