When your engine was new compression was about 120 and oil pressure 45. What you have now is a well worn 72 year old engine. The amazing thing about Chrysler built flatheads, is their ability to keep running in an advanced state of decay without knocks or bangs, without making a fuss of any kind. They just get slower, hard to start, and burn more oil and gas.
If that motor was in a car you planned to drive from coast to coast, or use for every day commuting I would suggest you plan on a rebuild. Not right away but in the near future.
In your case it will probably last as long as you want it to and if it doesn't, you haven't lost anything. So I would suggest you change oil, check points and plugs and reset to factory specs, adjust carb and let it go at that. A little heavier oil might curb oil burning a bit but don't go too heavy, 15W40 is fine. The main thing is it should have oil in the crankcase, don't let it run dry.
One little odd fact no one has mentioned. Your tug was made in 1961, two years after they stopped putting those engines in cars. By that time they were only available as industrial and marine engines, and in some heavy trucks and military vehicles.