MPG boost modifications for a '96 Chevrolet Silverado?

[JamieH]

I just purchased a Chevrolet Silverado K1500 with a Vortec 5.7L and was wondering what I can do to boost the mpg. Cheap or expensive I just wanted to see if anyone has good ideas.
Notice how I put "modifications" in the question.

 

[StampySkunk]

Keep the engine tuned up, new platinum spark plugs, new air filter and most important tire pressure. Look at the max on the tire and fill to within 5 pounds of the max. Don't go by the sticker on the door jamb, they didn't make the tire. Tire pressure makes a world of difference.

 

[lowlevel]

The best modification is your driving habits. It's a big V8 and it's going to be thirsty.

 

[Roger]

You have the tires checked every few months for pressure, and you keep your foot off the gas pedal when you are flying down the road at the speed of sound, A light foot, a tune up (cap, rotor plugs, change the inline fuel filter that everyone misses ( it makes a difference) fresh oil and a clean air filter all make a difference.