I've been a mechanic for twenty five years. I've also been into quite a few poured babbit bearing engines. I've never seen bearing damage that could be attributed to detergent oil eating the babbit. Both of RichZ's engines have inserts. I doubt very seriously the previous owners ran non detergent oil in the last few years, but who knows? You might have a point on running it in the Massey, that engine might have a bypass oil filtration system. The Oliver, on the other hand, is new enough to have a full flow oil filter. It would catch any dirt you knocked loose before it hit the bearings. If you're worried about it, pull a valve cover or a side plate and see how much sludge is in the engine. I ran detergent oil in my 8N and had no problems until I tried to replace the pickup screen on the oil drain plug. Those problems weren't oil related, though. You've got to take the information you get from a lot of those old guys with a grain of salt. A lot of them still think alternators and disc brakes are a waste of time. I know one guy that won't use a timing light to save his soul. Ask him what he does on a computerized car and he'll throw you out of his shop.