Which part can you see blueing? The header pipe at the head will blue and yellow. This part is single walled header and is visible. the header part of the exhaust is double walled from the head to the slip on muffler. Chrome cover ar there so you don't see the blueing of the header. If you are blueing the outer chrome covers, see above posts... If it is just the edge where it collects from the head, thats normal. T100's and the like do not have the double walled header, and they blue for the first + 18", when properly tuned.
