What speed are you driving, and under what conditions (uphill, downhill, heavy load, etc.)? What you're describing as "ping" doesn't happen unless the engine is under road driving load. Tune the engine to normal specifications, and stop tinkering with it until it's possible to do a proper, on-the-road evaluation of the problem.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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