Project planning need help with transmission and rear end

I'm looking to get all my ducks in a row and wanted to get opinions on transmission and rear end. Right now I have 2wd 4.3l transmission(nv3500) and rear end with a 5.7l. I want to swap in a lsx motor and I would like to keep the truck five speed. What would be my best option from the motor back to the wheels? I would like to make good power and depending on funds turbo the truck. Thanks for any ideas.

T56 6 speed, use that extra OD the T56 has to offer .50 ratio vs .7 in most standard 5 speeds. This way you can go steeper in the gearing, like 4.10-4.56's depending on setup and still get KILLER mpgs on the highway