Guess The Compression Ratio
I added octane boost and the detonation went away. I checked the initial timing and it was set at 5 degrees advanced. Seems conservative. I figured it should be at 10. Total timing was about 28 degrees although I couldn't get a good reading here.
Seems to run great with the high octane stuff. I had to add almost 12 ounces (about 3/4 of the bottle) of 104 octane boost to less than 10 gallons of gas. I'm not sure what this brought the octane to, but it seemed to have did the trick. California gas...go figure.
There's a gas station about 10 miles from my house which sells racing gas...up to 100 unleaded up to 110 leaded. Looks like I'll be making trips to this gas station from now on for the 100.