I've heard a lot of rumors about the 2001 civic ex, cam gear.

Is it really adjustable??? What do you do when you adjust it, I still don't understand how this works and why it increases hp??? Can anyone clue me in on the simpler side of engines, cause there aren't any competent enthusiasts in most of albuquerque, and I'm looking for some useful knowledge...

Also, does a pro need to install and dyno AEM cam gears, cause I thought that AEM puts guidelines to follow, when installing the cam. I've done all the other work to my car, so why not this if I can do it... Any help, is much appreciated...