Used in combination with 512838 crankcase boring plate; Required for 84-99 Evo Big Twin and 86-03 XL models; Note: Also required is 512841 7/8" tall spacer for 84-99 Evo Big Twin models only Fits: 84-99 Evo Big Twin & 86-03 XL with 512838 boring plate (NU) Units: 1