I use the 2" TTI on my car with its 440/493 and you can change the plugs with ease on it. One thing I like about headers also is the cool off much faster then the exh manifolds do and no matter what a car has I prefer to do plugs when its cooled off some. And I am a header guy as I like the more performance of the headers. The good headers like TTI and the Dougs have thick flanges and don't warp like the headers of the 70's did. Good luck . Ron