It'll put a smile on your face so big it might never go away. :D
Seriously though, if you want to get better gears, I recommend looking for junkyard axles with them in it already. In the long run it's cheaper. Plus I never ever condone sinking any money into a dana 35 (which is likely the rear axle you have now) beyond brake pads and gear oil. They're weak and I hate them. :mad:
Also, the auto trans in your truck is an AW-4. :cheers: