I have a chevy 454 w/ a 4 barrel carter carb stock heads stock exaust it has 107,000 miles on it and the radiator is in good condition and the rest of the engine has been well maintained but i do race the engine often and it seems to run a little rich on the right side of my dual exaust ive checked the tube shape length and number of curves seems all fine when you stand behind my car you can hear and feel the right exaust tube much more than the left. what could this be?