dave, it shouldn't be too hard to swap ratios. if you know what rear axle you have, as well as the crown gear diameter, you should be able to call up your local parts store and have them order a crown and pinion set in the ratio you want. then all that is needed is to drive the pinion out, remove the crown from the differential case ( bolts are usually left hand thread) reassemble the gears, and set backash and contact pattern. if you have never done a diff setup, i reccomend getting a little help from an experienced person.
for how low, what are you using the truck for? if it is mostly highway and all you're looking for is mileage, hell go with some 2.78:1 gears. you will have good mileage, wicked top end speed, but absolutely zippo for accelleration. if you want the middle ground, say if you pull a trailer at all or feel the need for some accelleration, try a 3.42:1 or 3.73:1 ratio. still get decent mileage, and still have a bit of grunt when you mash the skinny pedal.
Last edited by sbchevfreak; 08-22-2004 at 12:09 AM.