I don't know if you have tried this but there are a few things that can give a little more power. Try a header and new exhaust, maybe a new intake. Also if the truck has a standard fan switch to an electric. That doesn't add power just frees some up. Anytime you get ride of parasitic drag you free up power. Underdrive pullies, light weight drive shaft, or electric water pump. It takes horsepower to turn things like that, & the less power it takes to turn those things the more you will get at the wheels. Another cheap trick is better grounding. There are places that sell grounding kits, just a bunch of wires that go from the neg post on the battery to differents spots in the engine bay, but I just make my own. Believe it or not that's good for almost 5 horse power and better fuel milage, I have seen the results on a dyno. If you do all of that type of stuff I mentioned it should be good for 15-30 horsepower. Most of that stuff can be done fairly cheap.