There is a little mistake with the semantics in the above responses. The higher the rear ratio number, the lower the gear ratio. In other words, a 4.10 ratio is lower than a 3.23 ratio. A low gear requires more rpm to go the same speed as a higher gear. In the same way that the first gear in the 4 speed transmission is considered low gear but it has a 2.65:1 ratio as compared to high gear, which is a 1.00:1 ratio. The high gear takes less rpm to go faster. For drag racing, the hole shot is affected by the overall gear multiple in first gear. A 3.91 x 2.65 has a 10.362 multiple vs 3.23 x 2.65 or an 8.56 multiple. The lower 3.91 rear has more than a 20% higher multiplication factor than a 3.23 which gets the tires turning faster and the rpms up into the peak torque range a lot faster than a 3.23 ratio. The T/A Challengers and AAR Cudas came stock with 3.91"s. It's a great rear ratio for overall performance.
