Except for the PCM ZR-450 ("6.0L HO"), which has a PCM-specific cam, I believe all the 5.7L and 6.0L engines being used by the different marinizers all come from GM with the same long blocks. The difference in hp shouldnt be huge, as the only differences lie in the exhaust and ignition systems, and the tune that theyre running (air/fuel curves). I doubt youre going to see huge variations in hp like the #'s on the 5.7's in that chart would suggest.
The proof will be in the pudding PT... we'll line that new tug up against the local 196 6.0L and see what she's got. What prop came on that thing?