Hi, new here. I have a '50 4100 chassis cab..used to be a small fire brush truck. Has only like 2500 miles! I built a flatbed for it. I would like to swap out the rearend..or whatever you guys think. It's geared soon low. Would like to drive it at highway speeds. Thoughts? Was thinking of putting airbags on it as well to improve the ride. It's a dually. Thoughts on different axles? Wheels? Thanks