I am trying to break a speed record with a three point hydro airboat, I know this is an airplane tread so figured you guys would know what the fastest airplane engine around a .90 or engine of equivalent weight would be for my application.I read that the JETT engines were powerful but expensive. Ive got a flatbottom airboat gps'd at 45.2mph with a .61FX, I would like to get into the 70's so I need the most extreme airproped engine I can find. Any help with this one would be greatly appeciated.

Here are some pics of my current boat....