Wilwood Front Superlite 6R Brake Kit for GM AFX ProSpindles, Black Calipers, Aluminum Hubs and 12.88-Inch GT Rotors (Listed 1964–1974 Applications)

The black Superlite 6R kit brings six-piston radial front calipers and 12.88-inch GT slotted rotors to the listed AFX ProSpindle applications. Aluminum hubs and separate rotor hats are supplied, with BP-20 pads as the GT package's friction specification. This conversion requires the matching Wilwood spindle and a suitable 17-inch or larger wheel. Hose selection and system balance remain part of the vehicle build. Founded by Bill Wood in 1977 and based in Camarillo, California, Wilwood Engineering designs and manufactures disc brake systems for motorsport, street-performance and specialized applications. Its calipers, brake rotors, master cylinders, valves, fittings and brake lines are selected to suit the complete braking system.

Technical Details

• Manufacturer part number: 140-15910. Quantity: one kit for the stated axle/application.
• Supplied hub assembly: Hub - Hat Mount, aluminum, bare finish.
• Wheel mounting patterns: 5 x 4.50; 5 x 4.75 inches.
• Minimum nominal wheel diameter: 17 inches. The wheel must also clear the actual caliper and rotor profile in the installation drawing.
• Rotor specification: 12.88-inch outside diameter × 1.10-inch thickness; GT slotted faces. Spec-37 Iron construction; GT 48 Curved Vane design; published vane configuration: 48 CV.
• Rotor hats: aluminum, black e-coat finish; Big Brake Hat - Flared Bell. Hat offset: 1.500 inch.
• Service caliper: Forged Narrow Superlite 6R; 6 pistons; stainless piston material. Radial mounting, black powder coat finish.
• Published piston bores: 1.62, 1.12, 1.12 inches. Supplied pad compound: BP-20.
• Caliper hydraulic inlet: 1/8-27 NPT.
• Brake hoses are not included. Manufacturer line-kit reference(s), sold separately: 220-7056.
• Mounting hardware and the specified pads are included. Spindles, master cylinder and brake booster are not supplied.

Fitment & Compatibility

Use only with the documented Wilwood AFX ProSpindles on the listed GM A-, F- and X-body applications. The manufacturer identifies the primary groups as 1964–1972 A-body, 1967–1969 F-body and 1968–1974 X-body; individual rows retain their specific year and model limits. The required aftermarket spindles are not included, and original spindles are not an equivalent interface. Verify wheel-bolt pattern, hub contact surface, caliper clearance and the completed hydraulic balance. Use the complete application table below for the individual year, submodel, brake configuration and note attached to each entry.

PMB Performance has over 20 years of experience working with parts and fitment details. Provide the actual brake hardware, mounting dimensions and wheel measurements when requesting help with this conversion.

Manufacturer documentation: Installation instructions.

Manufacturer Warning

Applicable to brake pads only: Wilwood warns of exposure to arsenic, cadmium, hexavalent chromium compounds, lead, nickel, cobalt and antimony trioxide, chemicals known to California to cause cancer or reproductive harm. More information: P65Warnings.ca.gov.