Ultimately, cooling is the limiting factor of diesel tuning. The Yanmar marine version of the 1HD-FT reliably puts out over 300bhp and 700nm of torque but obviously benefits from much more efficient intercooling.
I'd love to see a dyno print out on where the power and torque curve is...
Having spent a bit of time in RIBs with this engine I get the impression that the max power is delivered at fairly high revs.... if it uses the same pump then someone like Colchester Fuel injection would be able to set an FT pump and do the nozzles to suit.... it might be horrible to drive though with all the characteristics in the wrong place
The power and torque curves look pretty impressive, maybe not as steep as LC spec engines but more power and torque across the board.
I agree that marine engines usually spend long periods at constant rpms and are tuned for such use rather than being up and down the rev range as in a car/truck with a gearbox. Yanmar specs