Originally posted by Hector:
You notice a hell of a difference when you install a header and have no resonator. 
There's a lot of mass in the stock exhaust manifold. I wonder if it's the shape or the mass of the manifold that makes the difference in sound. Many years ago, I made a straight-thru 'muffler' out of a 6 inch steel pipe, about 3 feet long, probably 1/4 inch thick. It was so heavy I had to bolt it to the frame, but it sounded really good.
