W.W.Williams' Marine Power division has a new line of marine diesels
available, the Optimizer 6500, produced by MarineDiesel-USA in Stillwater,
OK. The engine line has 6.5-liter, 8-cylinder blocks with 170 to 400 brake
horsepower that are the marinized version of the rugged Humvee military
vehicles. The engines are compact, lightweight and designed for repowers as
well as OEM installations.
"It is the ideal 'plug and play' repower engine for most GM-based marine
engines," said Aven Sharp, Vice President of W.W. Williams. "A typical
repower can be done in an 8-hour working day as it is a direct bolt-in
replacement. It is also compatible with most of the major stern drive
products in the market."

A center-rise exhaust system helps simplify conversions, as do the
standardized electrical harness connection and the engine and bell housing
mountings. The durability of the long-life cycle of diesel engines coupled
with performance similar to that of larger, gasoline-powered engines, make
the Optimizer 6500 a definite option to consider for repowering, even before
adding in that it has one of the lowest fuel consumption ratings in the
industry.

http://www.theboatingnews.com/0404EngineSpecial.html