Ive been looking into ethanol alternatives myself. Here's what Ive been able to figger out so far:
Any ethanol/gas mix 85/15 or 100 will require 12:1 compression at least, and hotter spark. You will also probably need all of the parts that such a high compression engine requires: new crank, rods, etc. Bigger jets for sure.
No rubber or plastic in the fuel system. Some plastics are okay, but why risk it. The ethanol is highly corrosive to most plastics though, and that would include the floats in yer holley.
Ethanol burns much much much much cleaner that gasoline, you can darn near drink the water that comes out of the tail pipe
Ethanol requires 200 proof alcohol that is almost impossible to still with any at home setup without a molecular seive. You can only get something like 190 proof with home stills, which aint good enough. It'll sure get ya drunk though.
Ethanol fuel needs more heat to vaporize in the intake than gasoline. This, to my understanding is the biggest hurdle, and makes cold starting really difficult. Some solutions have been a secondaray gas only starting system that switches to ethanol after startup, or a heater setup that heats the fuel up before the carb, and uses exhaust gasses to maintain the heat.
Ive heard of people converting slant 6's with off the shelf parts to ethanol. I dont know about Ethanols oomph factor, but I cant really understand how different if would be with such a high compression "performance" engine you need just to run the fuel. Ethanol is an approved fuel for many racing circuits, and the entire country of Brazil has been running Ethanol for almost a decade (its how they solved their sugar export crisis). Ive got a good idea of what to do with all the corn we have sitting around....
