New Old Stock / NOS mopar 8-3/4" ring and pinion gear set. These are 40 plus years old and are New original mopar parts...part numbers 1828722 and 1828724. The pinon gear is the 1-3/4" stepped and is for high performance 742 carriers...sure-grip etc. The ratio is 3.15:1...that's right 3.15 to one. I am not certain what years this ratio was offered...1957 1958 1959 1960 Dodge, Plymouth, Desoto, Chrysler, Fury, sport Fury, Super D500, 300, Golden Commando 354 392 L350 ? These are relatively rare and could be the perfect highway gear...compromise between 3.23 and 2.94. These would be great for any car particularly for a b or c body big block car. The condition is excellent. There are only a couple of very minor spots of surface rust...nothing that will affect performance. Nice addition to any correct restoration.