You dont think you can get 500hp outta a 6.0?? Come on now, you could make a perfectly reliable 700 hp 6.0...
Just a thought. But yeh you could sell that pretty easy i would think.
Get an oasis report. That will tell you the service history. If its been in multiple times, run away. If its been clean its ok. 03's and 04's were the worst ones, but there are many good ones outta those years.