Doug, you're at about the same place as Rommel was a short time ago. Check the "Timing Questions" thread. You should find some useful info.
Very useful info in Rommel's thread there is no doubt. I do need to point out that there is a difference between Doug's and Rommel's though. Doug has a 10-1 and Rommel's is 9.5-1. This 'can be' a significant factor. Come on Doug, pony up the extra $46 sents a gallon and see if the spark knock goes away. If you use octane to end the spark knock then you may find that you have more power because of it. I say this because it's the way my engine is. And I have to address the good point made that all engines do not perform better just because you add octane. BUT, some do.
It already went away with the disconnected advance. Therefore if the advance is still disconnected and he notes an improvement that would indicate he is still getting detonation that he is not detecting (I am assuming he is going by ear). This is entirely possible because under WOT you probably won't hear it. The way to tell would be by looking for white spots on the spark plug. In this case you are stuck with paying extra for fuel.
This is an excellent point that doesn't get stressed enough. Even if you can't hear it you may still be causing damage. That's one reason to err on the side of higher octane. Especially when you are on the ragged edge with a 10-1 engine. What if your tune 'slips' a little and you are getting detonation you can't hear because you have pushed the envelope? Yep, you guessed it, the engine will need to be rebuilt......
