when you hit nitrous you lose a lot of things, bearings, valves, cams...... but if you're running nitrous, your engine should be built to a point already that its not pulling much vaccum, so you might want to use a mechanical advance, and a double pumper.... probably suit your vehicle more... and remember, everytime you give her a shot of nitrous... consider it giving your engine about 10,000 miles of wear in just a few seconds