i was under my blazer today and cleaning off chuncks, i look at the tag on the rear diff. 43-14 3.07 wow i always thought is was sluggish off the line but how small of tires would have come on this to give it an advantage, cause i thought 31's were about stock.
prolly 30's stock. the gearing was for slightly better mileage. Your running at a slower rpm when at highway speeds. its basically a trade off, especially because its a light weight vechicle. the 3/4, heavy half and 1 tons are all gear much lower
I'm guessing you have a camper special or the factory tow setup on your rig. A lot of those packages have high gearing so that when your cruising at freeway speeds with a load the tranny can downshift still and get back in the power band. With 4.10s the RPMs are too high for it to downshift at freeway speeds.