Scoot,Yes You said what I think might be the reason for the ping,much better than I could get it in writing also.Now about the cam being advanced.The dist.is driven by the cam but adjusted to the crank at the damper,so if set to the same degree as the befor the change, that will still be the same.Don't mean it's right just the same.Now advancing the cam does close the intake valve sooner causing a little more cyl pressure at low to mid rpm which could add to Your problem.Cyl.pressure at high rpm will be how well the cylinders are filling,V E.I think it's time for a beer now.Bill.