Hi guys, does anyone know what the vaccum pressure is supposed to be on a vaccum advance?? When I suck on the vaccum line, it doesn't move usless I help it. I have a "knocking under acceleration" problem too. My timing is set at +28 degrees right now, to give me better throttle response. Any ideas?? Ryan Never knock on DEATH's door. Ring the bell and run...he hates that!!!!