Total invested so far:
-Plug wires ($89)
-Injectors ($0): Pulled from trashed intake manifolds.
-Injector hats ($32)
-New injector O-rings ($14)
-Ignition Coils ($0): Leftovers from buying/selling LS engines.
-Spark Plugs ($44)
-Header Flanges ($110)
-75mm Cable Throttle Bodies x2 ($70)
-MS3Pro wiring harness ($300)
Total: $659

With the sensors I need, plus a few misc connectors, I figure I'm probably $300 shy of having it running and tuned on the MS3Pro, putting me in at just under $1000.

With power steering/AC delete, electric fan, greatly improved ignition, aggressive fuel/timing and conversion to run on E85.. I'm hoping the original 389 HP comes out closer to 440 (I don't see this being any problem). The MS3Pro will be used to control the VVT for optimal power and torque.

Exhaust headers will be the very next step. It looks like 1.625" primaries in 16 gauge mild steel, with 6-1 collectors that merge into 3" (2.5" with a 3" expansion may be used). Primary tube length between 24 and 28" depending on problems with fitment on the driver's side. Possibly a custom X-pipe afterwards depending on the exhaust tone when finished. This should put me around 465-475 horsepower which is where you typically end up with 6.0 LS engines after just cam/headers.

Maybe I'll be able to break 500 with an intake manifold. Unlikely as the factory piece isn't very restrictive, but the runner length and plenum design leaves a lot to be desired.