I have a 1990 with a 302 and I believe it's pinging under full throttle. I've heard to advance the timing a bit, but I'm not sure how to do that. I know how to loosen the distributor and move it around, but do I need a light to adjust it "5 degrees". Also which way retards, and which way advances? I just want to play around with it a bit to try to get rid of the pinging.

Thanks a bunch
Jason