for 8.1 power- one word- Raylar. They are big into the 8.1 marine engine effort, and probably your best source for high performance 8.1. Yes, it will costs you $$. Go for it, different is good. I don't want to be like everybody else. My 8.1 Burb is a little different, makes lots of power for towing stock, and I think I can make a few mods and tune and it'll be even better. One thing I know for sure, I can pull out to pass somebody- loaded down with kids/full fuel/luggage, and it doesn't even strain! Nothing like that big block torque.

 

http://www.youtube.com/watch?v=BfA00Ih4zGg

 

If you could get parts a built 8.1(496) vz. a built 6.0 the 8.1 would bust that azzzzzzz lol