Gentleman,
I agree with John that if you are running a totally stock 216 or 235 an H or X pipe probably won't make a difference. On the other hand if you are driving a Six with higher compression, a modern cam, high voltage ignition, ect. you are in a different ball game. When I drop the hammer next to a 350 chevy I want every bit of HP I can get and even 4 or 5 hp makes a difference. You have to realize that John likes to keep things basicly stock, he always states that a vehicle is worth more stock than modified. Although I would have to debate that.
We are looking at this from two different places: Are we running a 300 horse six or a stocker. I use my sedan for touring and going to national shows. I sometimes pull a car trailer with my wife roadster on it so I have built my six to delvelope the horses required. I also run 4 wheel disk and radial tires which some people don't believe in.
In closing build your car to suit yourself as you have to put up with the end result.
