That's easy, right here at iboats. Props listed for 64 Evinrude/Johnson motors should fit. Size would depend on what size boat and activities. A boat intended for motors around 15 hp would normally require a 9" X 10" Your size should appear near the base of the blades or perhaps on the hub.Looking for a prop!!!!!!!!! 1964 Gale Buccaner 15 hp..Any clue where i can find one????????????