Originally Posted by
cadunkle
Nearly all boats have marinized car engines, even that Toyota boat you like. It takes a certain amount of power to move a given hull with a given weight through the water. To greatly simplify, do it with a bigger engine at a lower RPM or do it with a smaller engine at a much greater RPM. Fuel consumption will not be tremendously different at the same MPH. What is unreliable about a small block Ford or even a small block Chevy? These are engines that will go several hundred thousand miles in a car and lest plenty long in a boat. They are both simple and reliable designs that are very similar. BBF and BBC differ greatly, with BBF being superior, but still they're simple and reliable engines.
As for efficiency, your typical boat engine is so de-tuned that it's not going to be tremendously efficient. Up the compression, improve intake and exhaust and swap for a cam best for your usage and you'll see tremendous performance improvements and fuel consumption improvements as well
That eco boost will not go several hundred thousand miles like a 351w or 460 will, especially if you're towing heavy loads frequently. Too much HP per cubic inch and still low on torque compared to a normal sized engine. Look at SBF, 302 blocks split in half around 450 HP and as you approach that power level it's not nice to drive, doesn't idle smoothly and won't last long. If you want that kind of power a 460 is just getting started and will idle low and smoothly, giving potentially hundreds of thousands of miles before needing a major rebuild. 700 HP before a factory crank will fail, blocks can take a lot mroe before they become the weak point.
My point is, for reliability in an application that requires a lot of power and particularly torque, such as trucks and tow boats, you're far better off with a greater displacement engine with stronger components.