Any stock engine that goes too far into the water will die. The oil will float away and KABOOM. You need waterproof exhaust pipes that run above the water line, the transmission will need a hose custom fitted to the breather, vacuum lines (PCV valve etc.) clamped and airtight or deleted, dipstick tube glued in, the valve cover breather would need to be extended to above the water line, and the carb would need a waterproof air intake and housing and still might suck a trace of water (so I'd recommend F.I. setup). If you don't go in past the mid-section of the motor you can get away with just exhaust mods. P.S. If you're goin' floatin' weld your doors shut and add steps and don't forget to seal your gas tank spout good and get a waterproof alternator and battery.
