I bought this boat, and engine, 10 years ago in Sausalito, CA. Boat is now in Baltimore, MD. 42' William Garden design Porpoise Ketch (China Clipper type) Engine has always been maintained and runs, but I am refitting and wonder whether a rebuild on such an old, but running engine is worth it. Should I find a newer rebuilt Detroit Diesel, Perkins ? etc and install instead?Indifference, Steel, round bilges, old salmon boat