and for my thread, just click my sig pic - running a 5.3/NV3500 in my 99.
and if you're already DBW, just keep it. it will be a lot less hassle.
as for the harness, i got one with my engine & had Current Performance Wiring work it for my manual.
also, grab a flywheel off a 4.8 & a strong clutch (i hear centerforce has a good setup).
if you're plannin on making some real power (and are 2WD), you might wanna consider a T56 swap while you're in there.
edit: crap! i forgot the v6 trucks are all DBC... you'll need to talk with sleeper on that one