Not to go too far off topic but is there any header manufacture that kind of generalizes what type of power increase or power characteristics their headers produce? Years ago I was talking with Jere Stahl of Stahl headers of course and he told me that he worked a lot with producing the best power and torque for where the buyer was going to use, drive or race the engine he was making them for. Jere said that he used to go to circle track races and with a radar gun record the speeds in the corners and somehow calculate the rpm engines were running (don't know how he did it but that's what he said?) then talk to the drivers and I think he said he only found one driver that ever knew exactly what rpm he was running. He used a similar approach at making all of his headers and that's why he used the term “Total-Tuned” Headers. Is there any header manufacture that gives any kind of type of power or even a hint of type of power or power increase information? The only place I ever see this is with motorcycle 2-stroke expansion chamber exhaust pipes where you can get a pipe that will give you more bottom power, or better mid-range power or more top power for road racing or even motocross. Seems to me about the only info for headers is fitment. So when fitment isn't a big issue like a rail or fender well cutouts does the manufacture say "these will give you more mid-range power, or 10% increase in power or do they continue to say nothing but "they fit XYZ model from x year to y year?". In 1969 I put a set of Hooker Headers on my stock and new '69 383 Road Runner and they knocked 2 tenths off of my quarter mile times with no carb or any modifications. Same deal back then no header manufacture made any claims but fitment. I don't get it. As here in this thread the replies seem to be more about fitment than performance. Sorry just ranting a little or maybe the two cups of Death Wish Coffee talking

Mike