Not to discourage one on a mission to have an old style One Lung Diesel but ....
That engine was designed before 1927, IIRC. There have been a few improvements in engine design, efficiency and metallurgy since the Model T Ford went out of production.
While I am a big fan of the large slow diesel, I am also a big fan of the modern, high-speed small diesel. Used engines out of Japan are available, light, efficient, have real oil filtering systems and use modern, available wrenches and modern available fasteners. Many will last over 30,000 hours in over the road refrigeration systems being spun a lot higher than 800-1200 rpm.
If one chose to lower the operating speed, they would want to be sure the engine is properly loaded for the speed they are wanting to run and extracting the power they desire.
Personally, I'd build a unit with a 'bypass filtering system', very large air-filters and super filter the fuel. I think with these additions, a modern diesel could be run well over 100,000 hours with little or no problems related to the actual mechanical parts of the engine. One would still need to remember cooling problems are the most common problem of any Internal Combustion Engine.
Ron