Wilwood Six-Lug Front Superlite SRP System for GM Truck/SUV Iron ProSpindles, Black Calipers and Separate 14-Inch Rotor Rings (Listed 1963–1987 Applications)

The black SRP version of this six-lug front hub kit uses 14.00-inch drilled/slotted rotors and six-piston Superlite calipers with BP-10 pads. Its 6 × 5.50-inch aluminum hubs fit the specified wheel pattern, and the caliper brackets require Wilwood iron Pro Drop spindles. Confirm those components before using the vehicle application list. The wheel must accommodate the larger rotor and radial caliper envelope. From Camarillo, California, Wilwood Engineering develops disc-brake systems for street-performance, motorsport and specialized uses. Bill Wood founded the company in 1977. Calipers, brake rotors, master cylinders, valves, fittings and brake lines form part of its range, and must be combined to match the demands of the complete brake system.

Technical Details

• Manufacturer part number: 140-15946-D. Quantity: one kit for the stated axle/application.
• Mounting hardware and the specified pads are included. Spindles, master cylinder and brake booster are not supplied.
• Service caliper: Forged Narrow Superlite 6R; 6 pistons; stainless piston material. Radial mounting, black powder coat finish.
• Published piston bores: 1.75, 1.25, 1.25 inches. Supplied pad compound: BP-10.
• Caliper hydraulic inlet: 1/8-27 NPT.
• Rotor specification: 14.00-inch outside diameter × 1.25-inch thickness; SRP drilled & slotted faces. Spec-37 Iron construction; SRP Drilled Rotor design; published vane configuration: 72 CV.
• Rotor hats: aluminum, black e-coat finish; Big Brake Hat - Flared Bell. Hat offset: 1.380 inch.
• Supplied hub assembly: Hub - Hat Mount, aluminum, bare finish.
• Wheel mounting pattern: 6 x 5.50 inches.
• Minimum nominal wheel diameter: 18 inches. The wheel must also clear the actual caliper and rotor profile in the installation drawing.
• Brake hoses are not included. Manufacturer line-kit reference(s), sold separately: 220-7056, 220-11237, 220-12168.

Fitment & Compatibility

For this 14-inch SRP installation, identify the required Wilwood one-piece iron Pro Drop spindle before dismantling the existing brakes. The conversion will not fit the factory GM spindle. Six-lug wheels must match the 6 × 5.50-inch hubs and fully seat on the hub surface, with enough room around the Superlite caliper. The assembly changes stock wheel position: 1963–1970 applications move 0.41 inch outward, while 1971–1987 applications move 0.06 inch inward. Account for those dimensions when choosing wheel offset and checking body or suspension contact. Match the vehicle to the detailed truck/SUV application table below. Hoses and the required spindles are not supplied; arrange them for the actual build.

Use PMB Performance’s 20+ years of parts and fitment experience when checking a modified brake layout. The installed mounting hardware and measured wheel space are more useful than model and year alone.

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.