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You'll have to remember that the U.S. octane rating for gasoline is the average of the MON and RON numbers. That means 93 octane fuel purchased at one side of the street can be different than 93 octane fuel purchased from the other side of the street. That's because of the averaging that takes place to calculate the advertised octane value.

As a general rule, I'll not go over 9.5:1 static compression ratio for iron head rebuilds using 93 octane fuel but if the camshaft is on the wild side, then a higher static compression ratio can be tolerated simply due to the dynamic compression ratio getting lower as the intake duration on the camshaft increases. My general rule for dynamic compression ratio is 8.0:1 for 93 octane fuel. I did do an EMC engine in 2010 that was 10.5:1 static compression but 8.0:1 dynamic and ran fine on 86 MON fuel but this engine had 0.450" longer rods, a special dish design, and ceramic coatings in which to keep detonation at bay while using optimum ignition timing settings for power production. This was a dyno queen but the combination was optimized to run the lower MON octane fuel.