One more thing:
When you open her up with that big a motor, and your boat is lightly loaded, it may well want to act a bit funny, and "chine walk".
The large amount of torque will make the boat want to dig one chine in more than the other chine, which it actually wants to lift, because of the twisting effect on the transom.
The boat is planning, but more and harder on one side than the other, and it seems to have a mind of it's own. Time to throttle back a bit for safety's sake!
Joe. :teeth :thup