Torque1st, Can't agree with you on the tank size thing.....that calculator thing you posted is kinda interesting, but it doesn't give the whole story. Yes, ethanol contains about 2/3rds the btus of normal gasoline. But gasoline can only tolerate something like 9 to 1 compression, and thus burns at about 25% thermal efficiency. Ethanol, with a better octane value (R+M/2 is something like 115 ) and much higher latent heat of vapourization ( 3X gasoline ) can tolerate 12 to 1 with ease. This all gives an ethanol engine much better thermal efficiency, like 35-40 %. So if the gasser is taking in 120K btus and making usefull work out of 30K, and we compare that to the alky burner taking in 90k btus and getting 30-35K of work from it, alcohol can win in liquid miles per gallon, IF, and this is critical, the compression is high enough. An ethanol engine is also harder to start in cold weather, so where you live could play a part. Supposing one were to convert to alcohol and not raise the compression adequately, then, yeah, you would need more of it. The problem is that an 8 to 1 engine can be made to run either, but the 12 to 1 engine can't. DF, @ his Dad's house