Anyone here ever have their pistons machined?

I have repeatedly mentioned that 91 octane is the tops for easily available pump gas. Is 91 different in Idaho than it is out here in California?
I can get 100 at some stations, but it isn't enough.
Timing? I can see that you may have missed that I actually did cover that topic.....I HAVE tried different springs, different distributors, different curves and it didn't help at all. I tried different ECUs, different gaps for the reluctor, new plug wires, cap and rotor and the problem remained.
Again, with the 509 cam it knocked. With the 1.6 ratio rocker arms it wasn't any different though the cranking compression numbers became closer together. The change to the Lunati cam made things worse. Whatever "tuning" may have helped with the 509 cam would have had to been even better once the Lunati cam was in.
The point of this thread was to explore some options. For now I'm going another route.