Why don't more people build big cubic inch NA combos vs roots or centrifugal supercharger. With the cylinder head technology and intake manifolds and things of that nature nowadays you can make big Power naturally aspirated on pump gas also.

Depends on what you call big power, you're not going to see 1400hp unless you go 860 cubic inch.

, I was referring more to that 900 horsepower 1000 horsepower range.

I think you continue to compare drag race engine to marine, my buddies Top Sportman 632 made 1320hp with no juice and will push his door slammer to 203 mph on 3 stages.....put it in a boat and its a turd..........3200 lbs vs 10K,constant load

Then I'm guessing, lower RPM, milder cam, possibly more torque using a supercharger, more user friendly in a boat.

I have yet to see a 900hp or 1000hp N/A marine engine, go 250-300+ hours without pulling a valve cover. Plenty of forced induction builds that have done that, for many years. Also, that idle at 700rpm in gear all day.

so would you guys say in real world, a NA engine would be maxed out around 650 -700 HP to be dock friendly and reliable for a couple hundred hours, above that, need a blower to keep them dock friendly and reliable?
that would be my guess, right?

I am at 800+ HP with 598 CI and it idles at 750 RPM in gear and turns 6400 RPM at top speed. I did build it with the intentions of installing a supercharger eventually.

Sonnys makes a bunch rated for marine but ive never seen one in a boat.

https://www.sonnysracingengines.com/...s/boat-engines