Take a look at the Cummins Remans. It may be more money than you want to spend but check it out first. It may be cheaper than blowing a poorly hot rodded engine and you will have a fully warranteed engine.
I'll chime in here also. Adding a bigger turbo and aftercooler will not make a 330 or so engine. Certainly not one that will last. There is more to it than that.
The higher hp, 330 or so, engines that you suggested have different pistons, piston oil cooling jets, recalibrated pumps, and a whole host of other changes to make them last and work.
Don't look at the truck hot rodders or boat rodders. They make a short blast of a few seconds and get away with stuff that will blow up an engine that will be expected to run for hours reliably.
I'm no expert but I've seen this question raised many times on Boatdiesel over the years and Tony Athens and Paul Folston, both Cummins experts, will tell you basically the same thing.
You will also need to change the prop and maybe the shaft to take advantage of the extra hp or all will be for naught.
Do some digging and reading the older posts. Sure it's possible but very likely not effectively for long term.