3. The Gen III and IV engines do not use a distributor, but instead use a coil pack at each spark plug. This means the computer determines ignition timing as well as injection timing for each fuel injector. To monitor the stroke of the engine, a camshaft sensor picks up a signal off the camshaft in front of the LS2, while on the LS1 it is on the rear of the camshaft. There is also a crank position sensor that picks up a signal from a crank-mounted tone ring (be cautious of the LS2 from the '05 GTO as they have a different crank sensor from later LS2s).