High compression pump gas engines, I wouldn't be afraid to run 11.5-12:1 on pump gas with an EFI Alum. headed engine. I would do it with a carb as long as it was a good carb, with the proper fuel curve. There is a secret persay to running that kind of compression with pump gas. Must use an Alum head with proper combustion chamber design. Combustion chamber design includes the piston dish/dome, and the quench area. And the proper camshaft (Int. valve timing) Think in terms of all the pump gas turbo/super-charged engines. Some one mentioned all the new bikes with hi compression. Lots of R&D behind those designs. It is easily accomplished.
E-85 is a great performance fuel, Only a hand full of engine builders actually know anything about it, and the rest think they do. E-85 is an organic fuel, everybody thinks it is made of corn, but it can also be made out of wheat, sage, bean stalks, ditch weed, and any other dry flammable grasses. This is why E-85 is so inconsistant when it comes to octane rating. Know your fuel company, Heck I talked with the fuel truck driver at an E-85 gas station and learned more info/contacts than you can anywhere in regards to E-85. Working for my previous employer, we spent a great deal of time on E-85 fuels, This was when it first came out in early 2001.
11.5 on 92 octane pump gas.........I'm not scared.