"Since there are no gear and pinions available, my only option is a swap."
Not quite accurate. The available ratios include 5.14:1, 4.56:1 and 4.11:1. You most likely have a 4.56:1 ratio. A 4.11 ratio with a typical 27% OD transmission will give you a final drive ratio of 3.0:1. Keeping the 4.56 ratio and using an OD transmission will give you a final drive ratio of 3.33:1. I am not sure what ou are looking for, but if your rear is in good shape, you might consider a transmission swap for better speeds. With a transmission like the NV4500, your truck would have all the low end grunt of a truck, with the ability to cruise the higway.
