Why run a timing pointer?
 

Why do some folks run a timing pointer on an LS? I've seen them advertised, and started thinking about it more yesterday while I was installing an ATI damper with timing marks on fresh LQ4 based 408.

Because sometimes the crank trigger on the back of the crank isn't indexed properly when it's pressed on. If you're using an aftermarket ECU you can change the crank offset so you're not advanced/retarded from what the ECU is commanding. Factory GM ecu's have a procedure called the CASE relearn which helps the ECU determine the offset when the crankshaft is changed.