MARK Search Diagrams by Model HP/Displacement Serial Range KE7, KF7, KG4, KG7 - 1939 THRU 1953 ALL Go MARK 5, KF5, KF3 ALL Go MARK 6, 6A ALL Go MARK 7, KE4 ALL Go MARK 10, 10A, 15A, 28, 28A, 28AD ALL Go MARK 20, 15, KH7, WG7 ALL Go MARK 20H ALL Go MARK 25, 25E ALL Go MARK 30, 30E ALL Go MARK 35A ALL Go MARK 30H, 55H ALL Go MARK 40, KG9, KF9 ALL Go MARK 50, 50E ALL Go MARK 55, 55E ALL Go MARK 55AE, 55AM, 58AE, 58E ALL Go MARK 75 ALL Go MARK 75A, 78, 78A ALL Go