header tube size vs carb jetting

thanks guys, its a 406 chevy, msd , cam is about 256 / 245 ? duration @.050 about 550 lift i really cant remember exactly, 12.5 pistons, actual comp is about 11.5... 4000 stall, victor jr. bracket racer only... i just didnt want to waste time looking for a problem that isnt there ....thanks again.....