I'm just starting to learn about engines and high perf. parts and am trying learn as much as possible. I've heard that different lengths and diameter of headers can affect your powerband, torque and hp. Is this true and if it is which headers do what? I've also heard of exhaust scavenging, what is this and how can it improve or unimprove your engines performance?

Thanks.

 

Welcome to FTE!

I'd recommend lookin back on some of the old posts, there are lots of threads on this same topic.

 

generally the accepted theory is small tube makes better low RPM torque, big tube makes high end horsepower. small tubes create velocity and therefor scavenging to help fill up the cylinders with fuel better during the valve overlap, thats why small creates torque, but they don't flow well at high rpm when compared to big tube, which can really breath to make HP. for a truck you'd want smaller tube headers.