I am in the process of repowering my Pearson 10M with a new Yanmar 3YM20. The old engine is a two cylinder Farymann. I plan to keep the original fuel tank (SS), fuel lines, Racor filter and raw water strainers, control levers and cables, shaft and prop. Will have to go to larger exhaust hose, and modify the stringer beds a little. Boat comes out of the water early next week and I expect to have it running within 7 days with the new engine. I know this is not the same as going from gas to diesel.
I'm taking before and after pictures and will keep the group posted on the progress. I know there will be unexpected problems that will have to be dealt with.
I debated for a while on using a dripless stuffing box but finally decided to go conventional.