Ethanol again

The Ethanol Board claims ethanol will increase gas mileage. On new cars set up to run ethanol, how do we know? People choose to buy ethanol because it cost less. On an older vehicle I think mileage decreases. My reasoning is this- ethanol is an oxynginate. It adds oxygen to the fuel mixture. In a car not set up for ethanol the carbuerator must be enriched. If you add more fuel to the mixture, you are using more gas. This is a simplified explantion, but I believe it to be true. To go a little further in this line of thought, if you run an older (pre-smog) motor with modifications, it uses still more gas. In my pick-up, I have a motor factory rated at 350 horsepower. With the upgrades I have done, it's probably closer to 375 horsepower on good gas. When I work out of town and have to put 10% ethanol in it, it runs more like it did before the changes and the mileage went down.

The problem is when I refuel with unleaded and change the fuel filters, the symptoms don't go away. After three fill-ups it's still doggy. When leaded gas was used, the lead was a lubricant for the valves. Now on older engines, if driven, the only available options are hardened valves and seats, or lead substitutes. Makes me wonder whats so great about ethanol or unleaded if these things have to be done to less complicated engines.