Well FWIW, my 66-300 w/516's is advertized as a 10:1 motor that's still original except for a Hughes 2330 cam and I have some mild ping with 89 octane. Call me a cheap skate, but I dialed back the timing a couple degrees and run 87 with no problems. I do live on the left coast! Ya know as gas becomes cheaper in quality, your either going to have to de-tune or suffer the consequences with pinging because I can see that super will go by the wayside in due time. Sooner than later! Everybody talks about this and that with pinging, but yet they are so pigheaded that they refuse to de-tune to prevent the complaints that arise here and on other boards. As the old saying goes, "You can't have your cake, and eat it too", something has got to give!