[crxlvr]

for cams, duration is the term for how long that you have your intake and exhaust valves are open, the longer they open the more air/fuel can enter the engine, and the more it escapes, too much duration and the car will idle rough.

lift is the amount the valves will open into the combustion chamber, again the further they open the more can enter or exit, too much and the valves will hit into the pistons, unless you have special pistons that can allow for more clearence, you will end up bending your valves, and possible damaging the rest of your valvetrain.

dont go outrageous with these numbers or your car will run like shit, get numbers that are only a little bit higher than your stock ratings. If you ever heard a NASCAR car idling you will know what it sounds like with cams that are a lot higher then a stock cam, they run like shit at low rpms, but when you open it up, they run great, not recommended for a street engine, just something mild will do fine.