timing the same for headers set up? lack power?

Justin H. : My pipe circle diameter is 2 1/2 inches wide and the pipe exiting from the muffler is 2 inches long. My muffler choice I think it is called "Super Sonic". I'll take a couple pictures soon


about the back pressure thing, what does it mean? I would like to learn more about this. I would like my scamp to run smooth and strong as possible.