There is a link to my build in my signature. It's an '82.
http://www.lonniesperformance.com/82chevyduramax.htm
You will sink an easy $6-8K in the engine/trans. If you want to build it up, add another $4-6K without even getting inside the engine.
Inside the engine you can sink an easy $10K
You can do the Dodge axles & transfer case with some modification.
or the Factory Dmax transfer case with a late 70's Ford front axle.
Either way, plan on lots of work.