People have been extremely successful with E85. I've seen people making 600-700 whp. If it was available locally, I'd be running it. You need to burn ~33% more of it than gasoline, so any cost savings are roughly negated by the increased consumption. Octane rating is usually quoted in the 105-110 range. It's essentially 85% alcohol and 15% gasoline, but in the winter months they dilute it more, which makes the motor start/run better in the cold, but reduced the octane rating naturally.
You have to be sure everything in your fuel system is alcohol compatible. And since you have to burn so much more fuel, you need a much more robust fuel pump and injectors than you normally would for a given airflow.