[Big Dave]

The late, great John Lingenfelter did some work on high performance Chevy engines running on both straight ethanol (actually denatured alcohol) and E85.

He took a LS7 engine (7.0 liters 505 HP from GM) and modified it for alcohol. Obviously he jacked the compression up to 14:1 and advanced the ignition timing a bunch, but he also addressed the power loss by installing bigger fuel lines, pumps, and injectors. Result: 800 HP and he claimed the thing was more fuel efficient on a HP/MMBtu heat input basis. I’m sure he had no corrosion issues.

I would believe the increased efficiency at a very high compression ratio.

John Lingenfelter is dead, but his company still modifies Chevy engines. They might (for a price) work up an alky engine for you.

Maybe the best approach for a high-MPG alky engine is a very small engine with insane compression and/or turbo boost, but to keep the driving characteristics good, you gotta have a bigger injection system.

To burn alky efficiently, you have to sacrifice the dual-fuel capability. I’d also recommend a big fuel tank because you don’t know where the next E85 pump is.