On average (or better) how much power is lost through the drivetrain? Better yet, what could I expect to loose?

I have a 3200 converter, 4l65e tranny, going through a part time transfer case (NP201, or NP204 I think. Its the manual floor shift one) and to 4.10 gears.

 

you can normally expect about 15% power loss through an automatic tranny. You may see a bit more loss because of the converter if you dyno it unlocked.