usafhg wrote:
This is in response to a thread that was discussing the limits of
naturally aspirated HP in a 305 c.i.d. engine.

Well, first, I must confess I don't know too much about recreational
boating engines specifically. However, there is much in common between
car and boat engines. As far as reliable operation is concerned, lets
look a moment (bear with me) at the Infiniti G35 VQ 3.5 liter 6
cylinder engine. Normally aspirated, it puts out 300 HP (up from 260).
And it has been rated one of the top engines in a car under 50K for
about 10 years. Now I realize it isn't apples to apples. The air
intake might be more restricted in the boat engine without a fair about
of help--I don't know. But the point is today's engines are more
advanced, without the bolt-on technology enhancements.




Marine and aircraft engines operate in a completely different
environment than automotive engines. They often run at or near full
throttle for hours on end and if the motor breaks down at sea or up in
the air you can't simply pull over. For this reason the motors tend to
be derated somewhat from what the blocks are actually capable of producing.