If the bores are straight and round, no issues with using a quality ball hone and re-ring it. New alum heads are pretty cheap. Get them bare and have them build to marine standars. Cam/lifters are probably gtg.

plavutka likes LS engines. They have their place, but just not as strong as a BBC architecture.

I have a BMW X5 4.6is. V8 engine that is so complex it has many issues. The engine is massive. 4v heads. 2x OHC, with controlled phasing. Not that efficient, doesn't make a lot of power for 4.6L.

For med/high perf marine duty...there is nothing better than a BBC. GM was supposed to make a med duty LS BBC gas engine announced 2019. Covid likely derailed the plans.

My intention was not to criticize BB engines. I just wanted to point out that they are on the market so long because all the peripheral systems are adapted to these old engines. Any attempt to use a more modern engine is doomed to failure from the start, because along with the engine you would also have to develop a drivetrain with a higher gear ratio.
I’m not sure if I like LS engines as much as Tartilla think. They are just a compromise with which I managed to shed about 400 lbs of weight at the stern.
After my initial disappointment with the LS engine, which delivered exactly the poor results some forum members used to write about, I went looking for the reasons—because power is power, and why on earth wasn’t it showing in practice? I replaced the gearbox with a 1.56 ratio for one with a 2.04 ratio, and the LS really came to life. Later, I found out that Ilmor and Volvo Penta engines also have drives with ratios around 2.
I like this solution—I ended up with an interesting, almost 500 hp engine that I’m satisfied with. That said, I wouldn’t expect much more than 500 hp from such an engine. From an LSX, though, I’d dare to squeeze out a few hundred more horsepower.
This Lambo is certainly interesting, but due to its high revs, it’s inevitably bound to have a fairly linear torque curve, and during acceleration there will always be less torque than with a BBC. However, it will pull all the way to the top—provided there’s the right gear ratio between it and the propeller. And here we are again at one of the two main problems. The other, in my opinion, is the exhaust manifold.
For Cigarette from this discusion I would never use another engine than BBC.

That BBC engines are no longer keeping up with the times has been confirmed by their biggest supporter, Mercruiser, with its lineup of high-performance, lighter outboard engines.
I believe that Mercruiser would have switched to LSX engines long ago if they hadn’t made the smart decision to go for outboards, where, with the same number of boats sold, they suddenly doubled the number of engines sold.

Maybe think about using a pair of Porsche 3.8 turbo motors between the boat tax+ Porsche tax + tariffs you would be making so much money you couldn’t spend it fast enough.
I’ve never owned a Lamborghini but I can’t imagine the Lamborghini tax X 2, it’s hard enough to get quality work on a car let alone in a boat but that’s just me .

Absolutely love the idea of swapping different engines into boats. So much potential!

Sad, but true:

When a new industry begins to develop, many providers appear. The more the industry develops, the larger the investments become and the faster the progress. All of this eventually leads to a point where smaller suppliers can no longer keep up; in the end, only two—or at most three—suppliers remain, while some specialists can compete only in very specific market niches. For example, in competitions… and even then only if that niche does not generate extra profits.