This is Wilwood's Forged Narrow Superlite 4R (FNSL4R) rear big-brake kit, the drilled 140-9219-D version built for a Big Ford New Style axle flange with a 2.50-inch offset. The kit uses a radial-mount 4-piston caliper, a 12.88-inch rotor, and BP-10 compound pads. It is sold as a rear parking brake kit, so the rear hardware keeps the car's emergency brake function. Stock rear drum hardware cannot match the clamping force and heat capacity of a four-piston caliper on a larger rotor, which matters on track days and hard street driving. A flange-specific kit with a published offset also avoids the trial-and-error fabrication that cheaper universal rear kits often require.
Fitment comes down to two measurements. Wilwood's own listing names the Big Ford New Style flange and a 2.50-inch axle offset, and it tells buyers to verify the offset against its axle flange cross-section diagram because the kit may be offered in other offsets. The listing also specifies a 17-inch minimum wheel diameter. Search terms this kit matches include "Big Ford New Style rear big brake kit 2.50 offset," "FNSL4R 12.88 drilled rear P-brake kit," and "Wilwood rear parking brake kit 140-9219-D."
The manufacturer lists the kit for the Big Ford New Style flange at a 2.50-inch offset and advises checking your axle offset measurement against its flange diagram before ordering. Wilwood's sales and tech support line is (805) 388-1188.
The manufacturer specifies a minimum wheel diameter of 17 inches.
The manufacturer's listings show red drilled and polished variants of the 12.88-inch kit, with a black-caliper drilled version designated 140-9219-D.
The manufacturer publishes assembly instructions and a wheel clearance diagram for this kit. Review both before you start, and check your wheel backspacing and offset against the diagram so the 17-inch minimum wheel clears the caliper. Because this is a rear parking brake kit, plan to inspect the parking brake cable and adjustment during installation. Confirm with the manufacturer whether any hub, brake line, or master cylinder components are required for your build.
