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.
The distributor on your engine turns counter-clockwise. If you want to retard the timeing then turn the distributor case counter-clockwise. Turning the case clockwise will advance and probably make the pinging worse. You also might want to check to see if your EGR valve is carboned up. This could cause the pinging also. It's a pretty easy check and clean type item.