Howe 2 into 1 mufflers come in different lengths to meet various sound limits. All of the straight through design mufflers produce the same power and torque as an equal length of straight tubing the same diameter. When used in the combination with the Howe Y-pipe you will see significant increases in torque over fixed baffle mufflers. Bends and restrictions should be kept to a minimum after the muffler to maximize torque performance. All 2 into 1 mufflers have 7" cases.