Nice looking truck, matter of fact, except for the color it looks just like mine. I've got a '99 with the E-Tech 460. I've talked with a lot of owners of that same engine you have and most love them, same with the 427 mechanical. The great thing about the mechanical vs the e_Tech, is that you can fine tune your engine, where I can't. You won't need to waste money on getting the computer re-flashed, which for me has done nothing but lightened my wallet. Mileage wise, both engines do about the same. Grossed out going west, you can expect between 5.4 and 5.8 mpg. If you run at night west of I-35. In the day time, the easterly winds are a bit stronger, so you'll want to drive West at night and run east in the day time to take advantage of the winds. With a 1 to 2 ounces of acetone per 10 gallons of fuel, you should notice a mpg improvement of .5 mpg, at least I did, and my average went from 5.8 to 6.3 over the last 31k miles. Hopes this helps