castrol rs 10 60. Thats what was in my engine after a full rebuild and thats what ill continue to use. If it damaged the engine then surely the engine builder would know this and use something else.... If oilman is the same one as the other forums, he does not always have the same views as other people. I used to be on scoobynet and he was slated on there for sayin which oil was the best because he sold that one or somethin. I cant remember the exact story but it didnt make him look good. Ill just use whatever im told to use by the person who builds the engine.