Features & Benefits: Part Number: 54-71008 Brake Booster Diaphragm Style: Dual Diaphragm Diameter (in): 10.4 Diaphragm Diameter (mm): 264.16 Master Cylinder Included: No Master Cylinder Stud Thread Size: M10x1.5 Part Numbers : 1979-1980 18003678 18003681 18003686 18005029 18005040 18005055 For the Following Cars: .