The Wilwood Forged Dynalite front hub kit (MPN 140-12297-D) is a big-brake conversion for GM G-body cars that bolts into the factory disc spindle. It pairs a 12.19-inch vented, drilled and slotted rotor with a four-piston forged billet Dynalite caliper and high-performance Wilwood pads. Compared with stock front brakes, the larger rotor adds leverage and swept area, and the multi-piston caliper gives more clamping force for repeated hard stops on street, show, or strip cars. Choosing it over a smaller aftermarket kit means more rotor mass and heat capacity for heavier, faster G-bodies.
Search terms this kit targets include 1980-1987 G-body big brake front kit, 12.19 drilled slotted rotor conversion, Dynalite four-piston caliper G-body, and factory disc spindle front brake upgrade. Fitment is the key decision point. The manufacturer's G-body assembly instructions are written for 1980-1987 cars with factory disc spindles, so drum-spindle cars are not a fit. Plan on a machine-shop job: the stock steering arm and spindle must be drilled, tapped, and trimmed before the caliper bracket will mount, and the manufacturer recommends that a qualified machinist do this work.
No. The manufacturer's G-body assembly instructions call for drilling and tapping the stock steering arm and spindle holes and removing the C-shaped ears so the caliper bracket can mount. The manufacturer says this work should be performed by a qualified machinist before assembly begins.
The manufacturer's G-body disc spindle instructions cover 1980 through 1987 cars. Published year ranges for this part vary, so confirm the application with the manufacturer before ordering.
Difficulty is advanced. The manufacturer states that installation should be performed only by people experienced with disc brake systems. Start by checking the wheel clearance diagram, then raise and support the front end and strip the stock brakes to bare spindles. Clean the spindles and remove any nicks or burrs from the snout and threads. Per the manufacturer's G-body steps, drill the mounting holes to .332 inch, tap them 3/8-24 UNF, countersink to .438 x 90°, and remove the stock ears on both steering arms. Tools needed include a drill, fine-thread tap, countersink, and access to a machine shop. Use only the recommended hardware, apply Loctite where specified, and follow torque specs. Expect the job to take a substantial amount of time, so plan for the vehicle to be out of service for longer than a typical brake job.
