T-56 Close-Ratio 6-Speed: This gearbox is rated at 475 HP and 500 ft/lbs of torque and has a 2.97 1st gear, .80 5th gear and a .62 6th gear. This is an excellent choice for any XJ-S. Cars equipped with a 2:88 differential (most 5.3-liter HE cars) will see improved acceleration over the factory automatic, but not to the level of the TKO 500 5-speed. It is strongly recommended that the 6-speed be used with a 3.54 or lower (numerically higher) differential. All models will have excellent high-speed cruising ability in 5th and 6th gears. The 6-speed offers better acceleration at speeds between 80 and 125 mph than either of our 5-speed kits.