Finding a stock 7.3L truck isn't easy since so many people love to modify this popular engine, but we were able to find one that hadn't been messed with yet. Another pleasant surprise was the mileage. Really 158K miles isn't a whole lot for a truck this old. We put some windshield time in on her so we could record our fuel mileage, which averaged around a pitiful 9.1 miles per gallon before we touched her. We kept a close eye on this throughout the project and ended up improving Blue by over 6 miles per gallon, but we'll get to that in a minute.