Hi, I'm in Northeast Ohio and have usually taken my XK out on Lake Erie. From my paperwork, the boat was delivered to Cleveland Yacht Supply when new. So my boat seems to have been in the area since new.
One reason I asked about the distributor is that I don't recall ever seeing a marine distributor with a vacuum advance on it. So if you don't connect a vacuum supply to it, it shouldn't effect the way your advance curve/timing in the distributor works.
But it is very possible that someone replaced a marine style distributor for an automotive distributor since a F series CC engine would easily work with a standard Chevy distributor. The issue though is that typically a Marine Distributor (Coast Guard Approved) if spark proof to decrease the chance that if there is a fuel vapor problem that the sparks inside the distributor will ignite the vapors and ruin your day on the water.