I understand your confusion. I have a 1957 235 in the Blue Funk. I was told that oil filters were an option, in those days. A lot of dealers, as I understand, added them on. I believe it was recommended that the oil be changed every thousand miles in those engines.
Someone else, with scads of knowledge and resources will soon chime in. They'll be able to give you info on adding a filter to your engine. OR you can use the search option, for the time being. I'm sure there's all sorts of info there for others who "have been down that road before".
Good luck in your endeavors, Scot.
