Has anyone looked into changing the rear axle ratio? Is there a higher ratio (2.93 or so) that is common with another GM application? I'm not that concerned with the acceleration but I would definitely like to get better mileage. I've done this on other, older cars for racing purposes. I'm just not familiar with the commonality of current or recent GM offerings. I'm sure that the rear end on this truck is not a new design. The internals have to be common with some other applications.