Spec 99-04 Ford Cobra/ MACH / 01-04 Mustang Stage 3+ Clutch Kit

The SPEC SF873F is a Stage 3+ single-disc clutch kit for the 1999-2004 Ford Mustang SVT Cobra and Mach 1, plus the 2001-2004 Mustang GT built from February 2001 on. It is meant for 4.6L V8 cars that have outgrown the factory clutch: a blown Cobra with a pulley and tune, a nitrous or turbo GT, or a Mach 1 that sees drag strip launches. SPEC rates it at 875 ft-lb, which is far beyond what a stock clutch was designed to hold.

What the clutch kit does in a 4.6L Mustang

On these cars the pressure plate bolts to the flywheel, and a cable-operated release fork pushes the throwout bearing into the diaphragm when you press the pedal. The disc is clamped between the two and carries every bit of engine torque into the five- or six-speed. Stage 3+ is SPEC's carbon semi-metallic full-face material. SPEC positions it as the stage that keeps a full friction face for drivability and life while still holding big power, rather than going to a six-puck disc. SPEC lists this kit with its standard-effort pressure plate, so pedal effort stays closer to stock than a heavy race plate.

Symptoms that point to a worn or overpowered clutch

• RPM flare in third or fourth at wide-open throttle, especially once boost or nitrous comes in
• Slip on the 1-2 shift at the track when the tires hook
• Engagement point moving up the pedal, or the cable needing adjustment more often
• Chatter on takeoff from a glazed disc or warped flywheel
• Squeal or rumble with the pedal pressed, which points at the throwout bearing

How to confirm it before you buy

Do a high-gear pull from low rpm: in fourth at around 2,000 rpm, roll into full throttle. If the tach climbs faster than the speedometer, the clutch is slipping. Before condemning the disc, check the clutch cable, quadrant and firewall adjuster. A stretched cable or broken quadrant can keep the bearing riding the fingers and make a healthy clutch slip. Our slipping diagnosis guide covers the road test, and manual vs. automatic repair cost shows what the labor side usually runs.

Fitment

SPEC lists SF873F for the 1999-2004 Mustang V8 Cobra and Mach 1 with the standard-effort pressure plate, and the Mustang V8 GT from February 2001 through 2004. Check the build date on the driver door tag of any 2001 GT. Early-2001 cars fall outside SPEC's listing. Inside this range, the 2003-2004 supercharged Cobra and the naturally aspirated cars used different transmissions. Match your input spline and flywheel to the kit before install, and if you are not sure, send us your year and VIN. SPEC also builds a low-pedal version of this kit, so confirm which one your build needs. All Mustang clutch and driveline parts are in the rebuild kits and clutch category.

Install notes

At 875 ft-lb, the flywheel has to be right. A glazed or cracked factory flywheel will undo the new disc fast. Resurface it or replace it. SPEC's 99-04 Cobra and Mach 1 aluminum flywheel is made for these cars, and the Exedy 8-bolt lightweight flywheel is another option for 8-bolt cranks. Replace the pilot bearing, center the disc with an alignment tool, and tighten the pressure plate bolts evenly in a star pattern. Inspect the clutch cable, quadrant and fork pivot while the transmission is out, since a stronger plate puts more load on the factory cable system. Many builders switch to hydraulics with the McLeod hydraulic throwout bearing conversion for 1979-04 Mustangs. Refill the transmission with the fluid listed on its tag, then drive the car gently for the first few hundred miles so the disc beds in before any launches.

Does the SF873F fit my 2001 Mustang GT?

SPEC lists GT cars built from February 2001 on. Check the build date on the driver door tag. Earlier 2001 GTs fall outside the listing, so send us your VIN if you are unsure.

Will it hold a supercharged 2003-2004 Cobra?

SPEC rates the SF873F at 875 ft-lb, which covers most pulley-and-tune Terminator Cobras with room to spare. Confirm the kit matches your transmission's input spline before install.

Is a Stage 3+ disc harsh on the street?

Stage 3+ uses a full-face carbon semi-metallic material, not pucks. SPEC pitches it for drivability and life, so it engages more smoothly than a 6-puck Stage 3.

Do I need a new flywheel?

The kit does not list a flywheel. Resurface or replace yours. A worn flywheel is the most common cause of chatter after a clutch job on these cars.

Should I keep the factory clutch cable?

It can work if the cable, quadrant and firewall adjuster are healthy. Many owners upgrade the cable and quadrant, or convert to a hydraulic throwout bearing, when they move to a higher-clamp clutch.

• How to Diagnose Transmission Slipping
• Automatic vs. Manual Transmission Repair Cost
• Shift Flare vs. Slip: How to Tell Them Apart