Direct Factory Replacement: Designed to fit 1973–1977 GM midsize vehicles using 11-inch front disc brakes with an OEM 5 on 4-3/4 inch bolt circle Vented Cast Iron Rotor: Premium vented cast iron construction helps dissipate heat to reduce brake fade and maintain consistent stopping performance Complete Ready-to-Install Design: Includes pre-installed 7/16"-20 fine thread wheel studs and new bearing races for simplified installation OEM-Spec Dimensions: Plain face rotor with 11-inch diameter and 1-inch thickness for proper fitment with stock-style disc brake components Front Brake Application: Engineered for front position use on compatible GM midsize cars, delivering reliable braking performance and durability This factory replacement 11" front disc brake rotor fits 1973-77 GM midsize chassis. Has a 5 on 4-3/4" bolt pattern. Additional Note: If you require this rotor with the 5 x 4-1/2"Compatible with Ford bolt pattern see Part # 91031067.