360 timing questions

Is it overheating? What are you running for fuel?

Are you sure the timing marks are actually correct? That is one of the first things I'd do, you know how to use a "piston stop?"

Next I'd figure a way to tell what you have for advance. Either degree the balancer, buy the correct size timing tape, or buy a good "dial up" timing light. I don't like those, and don't use 'em. I always degree the balancer.

Are you SURE it's pinging and not an exhaust leak/ mechanical noise?

Does it use any oil? That will cause ping.