Does anyone know about these engines?
http://www.rotarypowerinternational....t/70rota~1.pdf

Seems interesting... light weight, small dimensions w/ 500hp.
And can run on diesel.

I used to have an RX-7 and the engine was smooth and bulletproof.

cool.
The 500 motor is almost 4 feet long, though. It IS about 6 inches narrower than a BBC but the exhaust will take up some more room on the side, eating some of that back up.
Height is short, but it's fat at the bottom instead of narrow like a v motor.
Weight is only slightly lighter than a BBC, and fuel usage is 35gph at 325 hp (a bit thirsty, as most rotaries have proven to be).

It's obviously got room for tuning for more power and swapping to gasoline.

But where would the rumble come from??

Can't have a muscleboat that goes: FzzzzzzzzzzzzzzzzzzZZZZZZZ!

bigyella

rotary as in Wankel?
or
rotary as in turbine?

It would be a poor choice for a marine application. It makes 250hp and is climbing at 6,300rpms when they cut the test off. The problem is that the torque peaks at 6,000rpms at about 210lb/ft. A mild small block chevy will make the same power at 4,500rpm and have about 100lb/ft of more torque at a lower rpm. My, guess is that it will also cost half of the rotary, but won't be nearly as smooth.