Interesting combo and it looks like you've been doing your research and made some good choices. I probably would not have gone MW ports for a boat engine but you have them and they aren't hurting you too bad at your size. I suppose if I was going MW port size I would've gone ahead and put a 4.25 stroke in it just to pick up some more inches but once again, you have what you have so now you just need to focus on the tuning.
Dwayne can get you the cam you need. The Lunati would probably work okay but if it was my money I'd just have Dwayne spec a custom roller. Only thing I see that I'd change if it was mine would be to drop the alternator down using a low mount kit just to give you a little more room at the top of the engine. With the mechanical fuel pump out of the way the alternator can drop down.
The block is near the end of its boring life, and I'd probably look more into a 572 setup if I wear this one out. So far, it running really good and lasting really well, considering that marine engines crank out constant power ie: cruising rpm of 3300 requires 200 hp input into the jet. Like I stated earlier, it runs really well and even out spins the LSA and Raptor 575 SC marine engines, but now its time to out spin the new LT4 :p ...naw, I'd like to see it brought up to its potential output as I originally intended as there is power left on the table, which can be handy when climbing up a class 5 rapid while loaded.
One reason why I prefer a N/A motor vs the supercharged motors like the LSA, Raptor, or the Hellcat crate I had considered marinizing, is a N/A motor is much more forgiving especially when it comes to 110* days and sub-par fuel (which happens a lot here in the Northwest). I even had to run on 87 octane in a pinch, however the motor did not hint or even record any ping on the computer datalog, though I tried to be dainty with it until I could give it a shot of 92 and octane boost...the same can't be said of the LSAs that filled up on 87. I opted for the Diamond pistons as they are a near perfect mirror dish of the EZ combustion chamber, which I am sure it bought me a little wiggle room along with the cold air intake, 34* total timing, and 12.5 AFR. However since that day, I keep a case of Torco octane boost in the storage compartment just in case I encounter another marina with sub-par fuel.
