I don't have any answers for you but I am very interested in your thread because I'm having the same problem with a 360 that is similar to yours, except that the best gas we can easily buy around here is 91 octane, and the engine really detonates on that. Ported "J" heads. No quench, I guess. I am going to pull the heads and inspect everything to make sure I haven't damaged anything with the detonation, and then decide what to do about it.