I currently have a MerCruiser 330hp 454 in my 1990 Rinker 236. Bravo 1 outdrive. Runs an easy 60mph with 4 people on board with a full tank of gas and Mirage 23p 3 blade prop at around 4300rpm. The engine runs fantastic, so there are no immediate plans to repower it, but I'm curious what it would take to run in the 70+mph range. Anyone have any BBC marine builds they can share?