unloaded, anywhere from 12-15 in the city, depending on tire size, right foot, and gears and whether it is a 305 or 350.
check the truck overy througholy for rust. around the cab corners are usually a good place for rust.
check the oil and trans fluid make sure they dont smell or look funny.
good luck with the search, the tbi motors are pretty good and very reliable. they are the most powerful compared to the vortec motors of 96+ but it would be a good truck.
2006 Chevrolet Silverado Ext. Cab LT3 VortecMax (LQ9), Black, K&N 63 series intake, 40 series dual in dual out Flowmaster, Leveled on 295/70/17, Line-x, SS cluster, corvette servo. Blackbear 93 Tune