ok I have bought a v6 4.3 five speed truck and want to swap out to an automatic 5.3 or 6.0

if I was to buy a complete dropout out of another truck harness, computer, engine and trans what all is needed to install into my truck basically transmission wise? I know I need mounts and accessories, and all involved with the motor swap but not sure about drive shaft, crossmember or will the wiring be there to run trans and speedometer? also what has to be done to the computer for this to work I plan on keeping my five speed column and just putting a floor shifter in to run the 4l60 or 80

as of now I have an automatic in the truck but is a 700r4 with the floor shifter. everything cranks and runs now but no speedometer, and just tired of this combination. I want to go to a electronic controlled trans and a v8!

 

anyone?