Forget it !!-----The basic magneto was used from 1950 to 1990.----The last models ( 22 cubic inch ) of these in 20 / 25 HP just moved the coils away from under the flywheel.-----They used a driver coil under the flywheel.----And there was room for an A/C lighting coil or battery charging coil.-----Other than that the mechanical pieces of the lo-tension and high tension magneto were the same.----The 6 HP high tension and the 25 HP lo tension magneto both use the same part # magneto plate.