WHAT IS IT?? - Construction is not unusual except for the water hopper which is round with an indentation in back for the oiler. Flywheels have 24' diameter and 2' face. Bore is 4-1/2' stroke is 6'. I acquired the engine in June 1974 from a man who had it only a short time, but thought it came from Montana. There is no evidence of a. name tag. The only casting number is on the rod, which I suspect is not original. Help - what, where, when, how big?? Thank you!