Don't overdo it on the high gearing. The engine will lug down every time you open the throttle, and put the metering system in the carburetor into full-power mode, and actually decrease gas mileage. Once the power valve opens up, fuel mileage goes down the tube. Let it wind up a little, and light-throttle operation should be pretty economical. Lug it, and you won't like the mileage at all!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!