ok, see if anybody can tell me what this may mean. i put new summit headers and dual 2.5 exhaust system on. with car running , if i put my hand up really close to the exhaust ends, one side makes my hand vibrate a lot more than the other side. both sides cause a steady vibration of your hand, but drivers side is alot more noticeable. it's a 67 with original 327. i have added new summit carb and intake, but have not touched the heads . any ideas? thanks.