I think MOST marine engines are built to run at higher AVERAGE CONTINUOUS RPM (AKA: cruising RPM) than are most car engines, but not higher peak RPM. A boat might well run at 3600-3800 for very long periods. A non-racing car is not likely to see that sort of sustained load.
And when I say "built" I'm thinking high-temperature valves, enough cooling to dissipate the heat, a torque curve with enough grunt to get up on plane at low RPM, and...I'm not sure what else. And even with such things in a marine motor, that only prevents it from grenading right away. It's still going to suffer a lot more wear than most car motors and the life span before rebuild will be far lower no matter what.
So, with all that, if your motor is a Chris-Craft-marinized offering that's been rebuilt per stock specs, 5400 sounds high to me. Without a cam swap, I'd think you'd be well down on torque up there and noticeably below peak power. 4600-5000 would be more my expectation of the desired WOT RPM, depending on which 350 setup it is. MAYBE as high as 5200.
But I'm half-guessing--others here will know.
"I don't have time to get into it, but he went through a lot." -Pulp Fiction