For now, stock '05 5.3L with F-body headers and cold air intake. Keeping it in it's stock configuration just to get it up and running. Then I'll throw on a LS6 intake manifold (already have) and a cam (undecided at this time) as well as a new torque converter.
Then when I financially recover from the intial build, I'm going to bore it out to 5.7L and rebuild it with forged internals and top it off with a kenne bell supercharger