GTX, set it up with the Noise Reduction package like the factory did. Not sure if 71's had it but they used a tighter muffler and turned down tailpipes instead of the chrome tips. You could tell everyone that it is stock on yours that way :):). I might still have mine in the basement, not sure if we used them on another car or not. I know I have the noise reduction stock 340 Duster mufflers still.
Tom