Maximum advance curve on my 360

What is the sylinder pressure readings? You can run what the engine allows. Things like sharp edges from a valve job, or excessive carbon, or too hot a spark plug heat range, being too lean or carb issues..the slipped or mismarked balancer...All could cause pinging. SO could faulty math during the build. If your psi is over 180 with the engine hot, the carb wired at WOT, and all 8 plugs out, it's a mechanical situation in the build. If it's below 180, chances are good it's a tuning or slipped timing mark deal. Lose outer rings on balancers slip backwards fairly often. So they will read a retarded amount.