3614371, used on forged crank engines from 1972-75. Appearance and dimensions are the same as above, the only difference is the pulley bolt pattern in the 72 and later, which is symmetrical. These continued to be used as part 3830183 for 1976-79. Another important fact is that even though six pack rods continued to be used up until 1975 in HP and truck 440's with steel cranks, they did NOT use this damper (#3512017, commonly known as a "six-pack" damper). any 73-75 steel crank 440 (with either six pack or standard rods) would have come with the 3614371 damper. We have found this to be absolutely true.