There are a few whacked HP Pontoon/Tri-toons out there. A friend had one with twin 2.5L race outboards. (What sucked is he snuck up on me and rooster tailed me at 70+ when I was cruising around 50mph!)
There are a couple that have run the LOTO Shootout with TWIN 496HOs, and one is twin 496HOs AND Pro-Chargers.