1978 Chevy K20 future build any help would be Appreciated!!!

[Cowboy Crash]

My grandfather gave me his first new truck when i was 16 and lets just say i beat it... bad... I regret it cuz not only is my truck closer to being a pos it also hurts my grandfather seeing it like that. After i return from army basic training in November i will have roughly $15000 to play with for a budget. It currently has an np203 transfer case (this has to go) a hydromatic four speed automatic tranny from the 60's(also has to go) and a 2002 chevy 350 vortec with the ecm (this is my arch enemy it will go even if i have to cut it into a million pieces.) it has dana 44's front and rear and needs new fenders and a new bed. I am thinking of putting a 383 pushin 5xx horse or a cummins?, a built turbo 400? and a gear drive transfer case(any suggestions). I am going to find new axel shafts(suggestions? I would love to have a lifetime warranty) posi's front and rear. I have rims that run 33x12.5x16.5 and would like to run 37" humvee tires so then comes the question how much of a lift do i need? truck sits at stock height.

Currently this is a farm truck that is used mainly for towing and off rouad use and is also my daily driver. I want her to be better than she was in her former glory and be able to see my grandpa look at his old truck and know its in good hands. pics coming soon. any further suggestions tell me and any questions feel free to ask. thanks Cowboy Crash