And you begin to see the mystery of fuels. Octane is not the only relevent factor. Keep in mind, you can get away with scary low octane on 300 ft drag shots, but 1/2 mile 20 lap ovals - 110 octane was insufficient for 14:1

ALSO..... MOST pistons are rated way over their actual compression, so one supplier's piston may work on low octane while another's true compression will NOT.

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another very important thing to consider is the combustion chamber and how it's going to handle and direct the gasses while they are being spent. port and chamber work can do wonders for fuels and they're effeciancy. a combination of compression,cam size and timing,port and chamber flow,octane and grade of your fuels. i've seen pump91, low comp ,ported engines run just aswell high octane,high comp engines without porting. well this is'nt a thread about porting and i'm not really an expert, i'm just jabbering. i do know that with the low comp engine i was running before that the high octane was killing me and when i pulled that one down the piston was loaded up and nasty. high comp version torn down 4 days ago was gorgeous on the same fuel....C12.