I stand behind what I wrote a while back.  The engine is badged a "Universal Atomic Diesel" when the 5411 was built.  This is because Universal were riding their reputation for the original gas engine Atomic straight 4 cylinder engines that they were famous for building a venerable, but dated engine design. It is a Kobuta block only.  Universal marinized the tractor block by installing an impeller housing, & on later models a heat exchanger.  They installed an alternator, Hurth transmission, fuel injection, filters, linkage, etc. so I think they have a right to call it a Universal.  If you go to Kobuta & ask them for parts for a 5411 they won't know what the hell you're talking about.  Its a Z400 Kobuta block.  Their parts are a lot cheaper, as Westerbeke now owns Universal & charges an arm & a leg for the parts.  Many engine companies source out parts as it just makes sense.  When they stopped building VW Beetles in Germany they still made them in Mexico, & it's still called a Volkswagen. Even when Frank Butler built his first boat, its design was from another manufacture, called a Coronado.  No one disputes that the C-22 is indeed a Catalina, because he said it was.