Spec 3/11-13 Ford Mustang 5.0L GT/Boss 9-Bolt Cover Stage 2+ Clutch Kit

SPEC SF503H-9 is a Stage 2+ single-disc clutch for the Coyote 5.0L Mustang GT and Boss 302 built from March 2011 on, the cars that left the factory with a 9-bolt pressure plate cover. It is for the GT owner whose stock clutch has started slipping in third and fourth after a tune, headers or a few hard launches, and who wants more clamp load without stepping up to a twin-disc kit. SPEC rates it at 705 ft-lb of torque capacity.

What a Stage 2+ clutch does in the 5.0L Mustang

The S197 GT drives through the MT82 6-speed with a single dry clutch: a pressure plate bolted to the flywheel clamps one disc, and a hydraulic concentric slave cylinder around the input shaft releases it. Holding capacity comes from two things, clamp load and the friction coefficient of the disc. SPEC's Stage 2+ step raises both over stock, which is why the 705 ft-lb rating sits well above what a stock GT makes. The trade is a firmer pedal and a quicker engagement than the factory clutch, though a single disc stays far easier to live with in traffic than most twin-disc setups.

Symptoms of a slipping or worn GT clutch

• Tach jumps ahead of road speed on a third or fourth gear pull
• Engagement point creeping toward the top of the pedal
• Burnt smell after a launch, a burnout or stop-and-go hill traffic
• Chatter pulling away, often from a heat-spotted flywheel
• Pedal that sticks low or a clutch that will not fully release, which points at the slave cylinder

How to confirm before you buy

Do a fourth gear roll-on from about 2,000 RPM at full throttle and watch the tach. If it runs ahead of speed, the clutch is slipping. Next, rule out the release side: a leaking or sticking concentric slave cylinder causes a soft or low pedal and a clutch that will not fully release, and no new disc fixes that. Our slipping diagnosis guide covers the road test. Hard shifts, notchy gears and lockouts are usually the gearbox rather than the clutch, which our Mustang MT82 problems page explains.

Fitment

SPEC lists SF503H-9 for the Ford Mustang V8 GT and Boss from March 2011 with the 9-bolt cover, through 2017. Our listing title covers March 2011-2013. The date matters: SPEC sells a separate kit, SF503H-2, for 5.0L cars built through February 2011 that use the earlier 6-bolt cover. Before you order, count the bolts holding your current pressure plate to the flywheel or check the build date on the door tag, and send us the year and VIN if you are not sure. This kit is not for the V6, EcoBoost, GT350 or 2018-up cars. More choices for the same car include the Exedy Stage 1 organic kit and the Exedy OE replacement FMK1026, all in the clutch and rebuild kit collection.

Install notes

• SPEC's product page does not list a release bearing, and the 2011-up GT uses a concentric slave. Replace it while the gearbox is out; the Exedy slave cylinder and release bearing BRG0186 covers 2011-2015 GT cars.
• Resurface or replace the flywheel so the new disc has a flat, clean face, and wipe it with brake cleaner.
• Center the disc with an alignment tool and torque the cover bolts in a star pattern in steps to the factory value.
• Bleed the clutch hydraulics with fresh brake fluid after install; see how to bleed a hydraulic clutch.
• Drive gently for the first few hundred miles so the disc beds in before any launches.

Planning the whole job? How much a clutch replacement costs breaks down parts and labor.

Will SF503H-9 fit an early 2011 Mustang GT?

Only if the car has the 9-bolt cover. SPEC lists SF503H-9 for GT and Boss cars from March 2011; cars built through February 2011 with the 6-bolt cover take SPEC SF503H-2. Count the cover bolts or send us your VIN.

How much torque will it hold?

SPEC rates SF503H-9 at 705 ft-lb of torque capacity.

Does it fit a 2014-2017 Mustang GT?

SPEC's fitment runs from March 2011 through 2017 for the V8 GT and Boss. Our listing is titled through 2013, so send us the year and VIN and we will confirm before it ships.

Is a slave cylinder included?

SPEC's product page does not list one. The GT uses a concentric slave cylinder release bearing, and replacing it with the clutch is the usual practice since the gearbox has to come out to reach it.

Will it fit the 3.7L V6 or 2.3L EcoBoost?

No. It is listed for the 5.0L V8 GT and Boss 302 only.

• Transmission Slipping Diagnosis Guide
• Shift Flare vs. Slip: How to Tell the Difference
• Automatic vs. Manual Transmission Repair Cost