Over the weekend i installed a DC sports header on my 2004 EX. I've checked for exhaust leaks and don't find any, but there is a strange sound at wide open throttle that i can't figure out. I've heard that these headers make a pinging kind of sound because of the thinner steel used. It sounds similar to that, but everytime i start to really give it gas, it sounds like marbles in a tin can. OH by the way this is my only mod to the car. Is this sound normal? I plan on checking for exhaust leaks again tonight. Any insight is appreciated.

Ben