Actually, at least in my experience, alcohol, in an of itself, doesn't really add that much HP.  I.e., if you just change the jets in the carb to accommodate the extra flow, you won't notice that much difference.

But, if you build with Alcohol/Methanol in mind, its something like, 160 Octane, its insane latent heat of vaporization, and the fact it will still make power when WAYYY off on the tune, makes it attractive.

Then, of course, there's the incoming charge cooling if you spray it upstream a bit, plus it can keep solid block cool for a long time ("long" meaning a couple of minutes - if the mix is proper).

And, his 2 Gal./mile, seems about right.  We used to figure 1/2 mile/gallon +/-.

Nuf said, fer now,

Knapp