I think most over octane their motors. I don't plan on running much more then 98-101 octane with 12.5:1. I will be mixing like Dom to keep it somewhat economical.
My 434" SB was built for pump 93 and is 11.2-1. When we dynode it I took 5 gallons of pump 93 and 5 gallons of crate 98 race gas. With no changes to the engine it made 30 hp more on the 93 than the 98. The afr and timing were optimized for the 98 before we tried the 93. I've tried unleaded 110 and it doesn't like it either.
I called VP last year and asked for a fuel recommendation for my combo, to my surprise they recommended MS109 oxygenated unleaded. I bought 5 gallons but ended up burning it in my SXS as my Dart didn't like it.
