I have added headers, 3" inch exhaust, performance mufflers, etc. Two cat. converter system. I also have a stage 2 performance chip, but I never re-adjusted my timing. Any suggestions as to where it should be set for best performance?

the new chip you installed should advance the timing to the right spot for ya, if you want you could try setting the base maybe +3 or so and see if you get detnotion at wot.

I changed the timing slightly to check for a change. I thought that the chip would control the advance of timing, but it would seem to be more of a rate of change rather than compensating for a more efficient engine. After making a slight change to the timing it made a HUGE change. Ever since I added headers I never had the same acceleration. I let you know when I nail down the optimal setting.