Wilwood Dual Dynapro Rear Drag Brakes for Olds/Pontiac Large-Stud Ends, 2.81-Inch Offset, Chevelle/442/Beaumont/Camaro/Apollo (1964–1974)

Large-stud lug-drive hats and dual Dynapro calipers identify this Wilwood rear drag package. Each wheel uses two separate four-piston calipers on an 11.44-inch drilled Super Alloy rotor, with the Olds/Pontiac housing end and 2.81-inch offset determining mounting. The listed vehicle applications require rear-axle verification rather than acceptance based on front-spindle equipment. Wilwood Engineering was founded by Bill Wood in 1977 and is based in Camarillo, California. The company designs and manufactures disc brake systems and components, including calipers, brake rotors, master cylinders, valves, fittings, and brake lines for motorsport, street-performance, and specialized applications.

Technical Details

• Manufacturer part number: 140-12556-D
• Type: Dynapro Dual SA Lug Drive Dynamic Rear Drag Brake Kit
• Calipers: Dynapro Lug Mount; 4 pistons per caliper; Type III Anodize.
• Caliper quantity: four total, arranged as two four-piston calipers at each rear wheel.
• Caliper bore sizes: 1.38, 1.38 inches. Piston type: Stainless.
• Included pad compound: BP-28.
• Rotors: 11.44-inch diameter × 0.35-inch thickness; Drilled; Super Alloy; Plain surface; solid, unvented.
• Rear housing end: Olds/Pontiac.
• Required axle flange offset: 2.81 inches.
• Wheel bolt circles: 5 x 5.00; 5 x 4.75 inches.
• Included: four rear calipers, pads, rotors, mounting brackets and assembly hardware, rotor hats.
• Hydraulic lines and fittings selected separately. No master cylinder, booster or spindles are supplied.
• Conditional wheel screening size: 15 inches. Use the installation clearance diagram to verify the actual barrel and spoke profile.
• Axle-flange limit: 6.29-inch maximum outside diameter with the specified 0.050-inch × 45-degree chamfer. Match the register and stud configuration to the exact installation drawing.

Fitment & Compatibility

Confirm wheel-stud permission before ordering: the current note specifies 0.64-inch studs, whereas DS918 calls for 0.68-inch studs. The selected hat's 0.700-inch holes are clearance dimensions. Match the flange pattern, bearing register and offset independently, then verify wheel clearance and the dual-caliper hydraulic circuit. This is a drag-racing configuration, with hoses and fittings selected for the completed axle and brake system.

Match the individual model, year, submodel and brake configuration in the fitment table below.

Wilwood installation documents: Installation instructions; Technical bulletin.

PMB Performance has over 20 years of brake-system experience. Contact us with your vehicle details and installed brake hardware for help confirming the correct arrangement.

California Proposition 65 warning, brake pads only: WARNING: This product can expose you to chemicals including Arsenic, Cadmium, Chromium (Hexavalent compounds), Lead, Nickel, Cobalt and Antimony Trioxide which are known to the State of California to cause cancer or other reproductive harm. For more information go to www.p65warnings.ca.gov.