GM Rear Disc Brake Conversion Kit, 1964-1972 GM A-Body, Premium Kit, Includes:, 11 in. Cross-Drilled/Slotted Rotors w/ 5 x 4.750 in. & 5 x 4.500 in. Dual Bolt Patterns, Red Calipers w/built in E-Brake, See Special Note Below|JEGS GM 10 & 12 Bolt Rear Disc Brake Conversion Kit for 1964-1972 GM A-Body [Premium Kit with E-Brake & Red Calipers].