I don't have a tach in this car so I have to guess that the pinging is in the 2,500 to 3,000 range I'm running 91 octane pure gas ( no corn ) My altitude is 3,200 ft. I'm going to retard the timing way back ( 6 or 8) and see if I can get it to stop pinging or see if it at least gets a little better. I will be about an hour and let you guys know what it did.