It was standard procedure for ultralight aircraft to break-in on Dino and then switch to synthetic. It was said that w syn break-in wouldn't happen as not enough wear would take place using syn for break-in. Could have been a wife's tale but I always did it. I used a motorcycle racing syn oil after break-in that was so viscous it wouldn't flow in oil injection systems that were very popular on motorcycles and other two stroke engines.
May be the same in a car or old trawler engine. I don't know.
By the way I said I saw a Lehman at Harbor Marine (where I'm he added now) for $15K ... But that's w a core or trade-in.
North Western Washington State USA