Blue color coded for average size. Stock replacement for all L77-89 B.Used as conversion kit on 90-99 Evo B. For 1989 and earlier type pinion shafts used on 90-99 Evo B. Models (engines that use S&S flywheels or other multiple parts flywheel assemblies) S&S offers this conversion package. Kits include a color coded 77-89 pinion gear, 54-89 oil pump drive gear, 54-89 pinion shaft gear spacer and a 54-89 pinion shaft gear nut. Note see: 531306 Black (smallest), 531308 Blue (average), 904148 Red (average), 531309 Yellow (biggest). Note: All kits must be used with a 73-99 B. Style oil pump driven gear (S&S 531209 / OEM 26345-73). Note: If the stock gear is unmarked and the size is unknown or you are scratch building an engine and without gear, S&S recommend a gear in the middle of the size range. These sizes were used more often and should provide adequate gear clearance under most circumstances. When in doubt, use a gear from the middle to the small side of the range, because a combination of looser fitting smaller gears will give a harmless clicking sound but to tight can cause a wining sound, binding and premature wear. Consult the factory service manual for information on optimum cam gear to pinion gear fit instructions before you order. L77-84 Shovelhead; 84-89 Evo B. Conversion kit for 90-99 Evo B. When using custom pre-1990 multiple parts flywheel assemblies (NU). We will accept your request at our earliest opportunity. This includes Republic Of Ireland. Please do not ask us to lower the value of goods this is illegal and we do not want to get involved in this kind of activity.