Having been down this road... a light boat and a 383 will get it done. My Chris Craft Stinger 222 went 77 on GPS (outrunning a nasty thunderstorm at that) with a 385, TFS heads, and a Comp hydraulic roller. We even ran a poker run with when the Bullet ate one of it's engines.
https://cimg0.ibsrv.net/gimg/www.off...cf654e96e.jpeg
https://cimg1.ibsrv.net/gimg/www.off...d6845bfda.jpeg

Okay, looked up the OP’s engine to get cam specs.
click here :
https://www.mercruiserparts.com/bam/...2006/13933/120

Then click on the #11 part #.
scroll a touch and you’ll see all the different engines it comes in.
The notables - 350mpi’s.

Here are the valve springs. Can’t find the specs but they come on lots of nothing special motors (4.3 tbi’s and etc)
https://www.mercruiserparts.com/483471-spring

Free shipping!
https://cimg5.ibsrv.net/gimg/www.off...6a4ead873a.png

Yeah probably not a good bet to try running them with an aftermarket cam. How is the rest of SBC valvetrain? Pushrods are cheap enough, but is the timing set up to the job?

Also, thank you to everyone for your contributions here. I may forego any modification, but then again, a 6.2 LS swap has been on my mind. Not sure how much I could sell a healthy 383 for, but I thought it may cover the cost. I don’t know about boats, but in cars, these engines not only run smoother, but I’ve recorded noticeable fuel economy gains.

Ai ^^^ ????!

Yuuup

Ten posts and most read like AI.

Yep that’s 100% AI based on my experience having the same conversation with ChatGPT. And actually, it seems like an aluminum 6.2 swap wouldn’t be terribly expensive or difficult given my experience and parts availability. I’m beginning to think it’s better than modifying the 383 since I already have the engine on hand. It’s fresh too…probably 2-3k miles. I’d just have to change the cam. 🤷‍♂️