This is a 40 / 90 NDenso Chrysler Externally Regulated Alternator With an 8mm Top Adjusting Ear Hole. Original Lester Catalogs Used Part No. 13184 to Describe the NDenso Unit With the 4-Groove Serpentine Pulley Only. Other Lester Numbers Were Used as Pulleys Changed. The 13184 is a "Base" Unit Which Other Lester Numbers Can Be Made Using the Following Pulley Changes:#121000-3300 (13184 - 290-236) 4-Groove Pulley#121000-3000 (13305 - 290-234) 5-Groove Pulley#121000-3310 (13305 - 290-234) 5-Groove Pulley#121000-3330 (13256 - 290-236A) Double V-Groove PulleyIf The 13184 is Fit With a 5-Groove Pulley (Lester No. 13305), it Can Be Used in Place of the 14869 (290-276A - 15mm Rotor Shaft and 8mm Top Adjusting Hole). A 13184, Fit With a Double Pulley (Lester No. 13256), Will Interchange With the 13185 (290-276 - 15mm Rotor Shaft and 8mm Adjusting Hole). A Unit Which Looks Just Like the 13184, But Has an 11mm Top Adjusting Hole, is the 13245 (And Other Lester Numbers Depending on Pulley).