Steve Baur
Former Editor, Modified Mustangs & Fords
April 1, 2008

One of the coolest things about a late-model Mustang is the manual transmission and its ability to be power-shifted with relative ease. From the T-5 to the T-56, 5.0- and 4.6-liter Mustangs offered a smooth-shifting gearbox that, when acted upon by a skilled driver, could reduce quarter-mile times by two or three tenths.

With the passing of time, it has become increasingly easier to make horsepower-and lots of it. Considering the stock transmissions were designed to handle 220-300 hp, the ease of increasing horsepower has provided transmission companies with lots of rebuilds and the need for aftermarket transmissions. That being said, it only makes sense that the critical element (the clutch) residing between the engine and transmission would need to be upgraded as well.

With regard to late-model Mustangs, the clutch assembly consists of several components, though most clutch kits generally feature only a pressure plate and clutch disc. When you press in the clutch pedal, a mechanical cable or hydraulic line acts upon a clutch fork. This fork rests on a pivot ball inside the bellhousing and is connected to the cable or line at one end. The pushing or pulling action from the clutch pedal makes the clutch fork pivot and press the throwout bearing into the arms of the diaphragm (or fingers) on the pressure plate.

The pressure plate is a spring-loaded metal friction plate that sand-wiches the clutch disc against the flywheel. When the clutch fork engages the pressure plate, the metal friction disc comes away from the clutch disc, which disengages the engine from the transmission. Clutch forks and flywheels are usually reused, with the latter possibly requiring resurfacing or replace-ment, depending on the mileage and usage. The clutch disc has a wearable material that allows a certain amount of slip, so that the transfer between gears is not excessively violent. This makes a car easier to drive and is easier on driveline parts.

Clutch technology has grown quite a bit since the musclecar days, with new friction materials and clamping concepts that offer extended power-handling capabilities, usually while maintaining a stock-like pedal pressure and feel. For cars with major amounts of horsepower (700 or more), many companies have turned to a twin disc design, where a single pressure plate is used along with two clutch discs and a floating spacer between them. This design offers more frictional surface area, which better distributes the power going to the clutch.

That being said, Muscle Mustangs & Fast Fords contacted various companies in the Mustang aftermarket to see what was avail-able for Ford's ponycar. In addition to clutch assemblies, you'll see that many of these companies offer other driveline components, such as flywheels, throwout bearings, and bellhousings, so if you're having trouble getting all of that horsepower to the ground, we're sure there's someone here who can help.

Anderson Ford Motorsport
To go along with its series of high-revving hydraulic roller camshafts and valvetrain, Anderson Ford Motorsport now offers a line of diaphragm clutch systems designed for similar high-rpm conditions. Available for 5.0 and 4.6 Mustangs, these 11-inch clutches allow you to shift your Mustang as high as 7,600 rpm without the worry of a negative centrifugal motion, which happens when your clutch pedal sticks to the floor during high-rpm shifts. In the past, one would move to a three-finger-design pressure plate, but strides in diaphragm design have changed this.

Applications include 5.0 Mustangs, as well as Two-Valve and Four-Valve 4.6 Mustangs, with prices ranging from $200 to $600. AFM also offers its SuperLight aluminum flywheels for the 4.6 and 5.4 engines, which are 14 pounds lighter than a stock 5.0 flywheel, and said to offer better acceleration and less shock on the transmission at gear changes.

Centerforce offers a multilevel product line, allowing customers to choose a performance clutch that matches their application and driving style. They are designed as an improved OE-style, direct bolt-in replacement performance clutch, and the unique Centerforce pressure-plate design allows for easy pedal effort and everyday driveability while offering increased holding-capacity for maximum performance.

Centerforce is probably most known for its dual-friction clutch assemblies, which have a full facing on the pressure-plate side for driveability and longevity, and a carbon-composite segmented facing on the flywheel side for a positive engagement and increased holding-capacity. Before you need that type of clutch holding, the company offers its Stage I and II systems. While beyond the dual-friction, it offers the DFX and LMC or light metal clutches.

The DFX line is aimed at high-end applications that continually demand increased integrity and holding-capacity, such as high-horsepower Terminator Cobras. Centerforce claims it does this while providing some of the best driveability and easy pedal effort from a race-inspired clutch. The DFX performance clutch system is SFI-approved for competition, with nodular-iron pressure-plate rings and reinforcements designed to help prevent drive strap breakage and safety.

Centerforce's new LMC (Light Metal Clutch) series is a low-inertia performance clutch designed to reduce engine rotating mass. These lightweight SFI-approved clutches were made with most road-racing and circle-track applications in mind, which is why we installed one in our own corner-carving project, Stolen Goods. Centerforce machines the LMC pressure plates from high-strength aircraft-grade billet aluminum and then attaches special heat-treated replaceable friction surfaces. A dual-segmented carbon-composite friction disc is utilized, and the pressure-plate assemblies use Centerforce's patented centrifugal weight system for maximum grip while maintaining a comfortable and controllable clutch pedal.

Centerforce also offers SFI-approved performance flywheels in both billet steel and aluminum, as well as its 400-Series flywheels, which are O.E. cast-iron replacement flywheels and not SFI-approved for competition use.

Fidanza is most known for its performance flywheels, but the company has recently hit the clutch market full force. Its most recent additions to the clutch family are a line of twin-disc clutch applications for the '86-'95 302 5.0; the '96-'04 4.6 GT, Mach I, Bullitt, and Cobra; and the '05-'07 4.6 Mustang GT.

These twin-disc clutch kits include the pressure plate, floater plate, and twin discs, as well as a lightweight performance flywheel. Fidanza Stage 1 assemblies are rated at 650 lb-ft of torque and Stage 2 at a stump-pulling 825 lb-ft. Fidanza claims the twin-disc clutches are engineered to tackle up to 800 hp with virtually no change in pedal pressure. Smaller 8 3/4-inch-diameter discs are used to control the rotating mass of the clutches while maintaining a sizeable surface area for optimum gripping power. Fidanza straps the floater plate on all of its clutches to eliminate the annoying rattle for which twin-disc units are known.

Fidanza also offers a performance clutch kit for the '05-'07 Mustang GT 4.6 in four different levels of performance. Each clutch kit includes a pressure plate, clutch disc, throw-out bearing, and pilot tool.

In addition to its twin-disc clutch systems, Fidanza also produces high-quality aluminum flywheels, clutches, cam gears, flex plates, CV shafts, and short-throw shifters for track, tuner, and street applications.

Ford Racing Performance Products
For years, the Ford Motorsport (now Ford Racing Performance Products) clutch has been a staple of the 5.0 Mustang community, and for good reason. It was relatively inexpen-sive and could handle a lot of abuse. It's not unheard of to see an FRPP clutch propel a 5.0 into the 10s in the quarter-mile, but that clamping ability came at the cost of a heavy pedal effort. Sitting in traffic with one is equivalent to a few hours on the leg press at the gym. There's no denying its handling power, and the pedal effort was addressed with the release of the King Cobra clutch, which uses a dual-friction disc to get the job done with lighter pedal effort.

More recently, however, FRPP released its '07 Shelby GT500 twin-disc clutch setup for 5.4 engines with an eight-bolt crankshaft. The company carries numerous clutch assemblies for everything from 5.0 Mustangs to '96 Cobras, and opening the FRPP catalog will show you numerous bellhousings, fly-wheels, and clutch cables and quadrants that are also available.

Hays Performance and Racing Clutches
Hays offers high-performance street/strip clutches for '86-'04 Mustangs, with greater clamping force over the stock factory units for positive clutch engagement. Diaphragm springs are used to assure light pedal pressure and quick release for precise gear changes. The clutch discs feature a heavy-duty organic lining to withstand heat and higher rpm, while the Marcel-style spring allows smooth engagement and steady torque transfer without chatter.

Hays also offers its Tork Loc 5.0 race clutch kit, which is a complete bolt-in setup that eliminates the problem of installing the desirable, long-style, adjustable pressure-plate assembly into a '79-'95 Mustang using an S.F.I.-approved aftermarket bellhousing and factory-style clutch cable and quadrant.

Designed for higher-horsepower vehicles using a turbo, blower, or nitrous system, this kit features an 11-inch, lightweight, fully adjustable, three-lever, long-style pressure plate with aluminum pressure ring to compensate for various track conditions and reduced tire slippage. A sintered-iron clutch disc provides a greater coefficient of friction for greater holding power and clutch longevity. The kit includes a 164-tooth, lightweight, billet-aluminum flywheel; a custom clutch-release fork; an adjustable fork pivot ball; and a high-performance throwout bearing. The assembly meets S.F.I. specifications for all racing sanctioning bodies.

Sharp eyes will have caught that Hays offers billet-steel or billet-aluminum flywheels as well. The aluminum pieces feature a replaceable steel heat-shield friction surface, and all flywheels are precision balanced to factory specifications and certified under S.F.I. specification 1.1.

Lakewood Industries
While Lakewood Industries doesn't offer clutches, it does carry the all-important safety bellhousings for racing applications, which are mandatory in cars running 11.99 or quicker. Manufactured using a hydro-forming process to maintain proper material thickness and minimize thinning in critical areas, these bellhousing are made from 1/4-inch steel and are heat-treated. Engineered to contain a clutch or flywheel explosion, they're certified to meet or exceed S.F.I. Spec 6.1 when used with the supplied block plate and fasteners. For your convenience, we have included part numbers at the end of this article for most of the Mustang applications.

Since the safety bellhousings are an aftermarket application intended for a racing environment, Lakewood also offers its custom-fabricated Clutch Release Fork. It's designed to allow adequate clearance between the fork and cover, which is necessary when installing a long-style clutch assembly into a '79-'95 5.0 Mustang. The clutch fork is constructed of heavy-duty steel to eliminate flex, and the zinc-dichromate plating helps prevent corrosion.

Working with the clutch fork is Lakewood's adjustable pivot ball, which is designed to allow additional adjustment of the clutch fork height to eliminate clutch release problems when installing a high-performance clutch. The pivot ball fits '79-'02 Mustangs and is recommended for use with Lakewood safety bellhousings.

Ram Automotive
Ram Automotive recently introduced its new street dual-clutch system for the late-model Shelby GT500. Ram used its race technology to bring a combination of friction and static pressure to hold extreme horse-power levels. The unique drive-system design allows precise location of the floater plate, just like in the Pro Stock clutch systems, yet virtually eliminates floater plate rattle. The street dual is capable of holding in excess of 1,000 hp with the base 300-Series discs, and it provides a smooth engagement for low speed cruising.

Ram also offers a host of clutches for Mustangs, ranging from premium replace-ments to serious street systems. Also avail-able is a hydraulic release bearing for Ford applications. The hydraulic bearings are designed for easy installation in applications with limited chassis clearance or when a consistent, lighter pedal effort is desired. The kits include the release bearing, mounting hardware, a replacement bearing collar, and a remote bleeder kit. Two models are available: one for the Ford T-5 transmission and one for the Tremec transmissions with a 1.425-inch-collar diameter.

Spec offers its Super Twin clutch assembly for street and track use in cars with extreme horsepower and torque. Applications include the new Shelby GT500 as well as 5.0 Mus-tangs, and Spec claims the clutches are built to handle 700-1,500 lb-ft, with near-stock driveability, tremendous life expectancy, a no-shimming/setup bolt-in installation, and maintenance-free operation.

An all-billet construction is designed to keep these units smooth and quiet, and the Super Twin is constructed with aircraft-grade aluminum and high-carbon-billet steel milled to 0.001 inch for perfect balance and actuation. Friction is provided by dampened, full-faced carbon graphite discs, though organic or full metallic options are available. A flywheel and track-spec hardware are included in each kit.

Spec recently released a Low Pedal Requirement (LPR) option for all '01-newer Mustang applications. The company claims its new pressure plate offers the same extreme clamping load as the standard unit, but with a 28 percent lighter pedal-a feel purportedly 5 percent less than the stock pressure plate. The LPR upgrade is available with all seven stages of clutch kits or as the pressure plate alone.

Also new are Spec's stock-appearing aluminum pressure plates, which are designed to allow for quicker revs, more horsepower, and increased engine reliability. They can be used with a variety of friction discs and are available for all Mustang applications.

In addition to clutch assemblies, Spec offers billet-steel and aluminum flywheels, which feature replaceable high-carbon-steel friction plates. The flywheels are rebuildable by Spec or the end user. Each unit is tuned with specific inertia requirements for different driving environments and modification levels.

Zoom Performance Products
Zoom has been making clutches for more than 40 years and offers several different clutches for '86-'08 Mustangs. The company's new ZVT (Zoom Variable Torque) pressure plate utilizes centrifugal force to provide greater clamping capability. Considering Zoom offers this technology for the Ford PowerStroke diesel, you know it has to be able to handle some massive torque. The company also manufactures its own line of lightweight aluminum flywheels.

The Custom Clutch
Until recently, many excessively high-horsepower applications required a custom- designed clutch assembly to deal with the intense load characteristics. As you have seen, many of the companies listed here now offer clutch assemblies that have incredible clamp-ing capabilities. In a racing environment, though, every ounce of weight and horsepower is figured in to the final equation, which also takes into consideration vehicle weight, tire size, and the powerplant driving the vehicle down track. Where every vehicle dynamic needs to be squeezed for all its worth, a custom clutch assembly may be your best bet, and companies like Advanced Clutches and McLeod can help. The clutch disc, pressure plate, throwout bearing, clutch fork, and pivot ball are all scrutinized to provide the best product per application. As you might imagine, the cost isn't cheap, but neither is winning.

Lakewood Industries Bellhousing Applications
Application YearEnginePart No.
{{{Mustang}}}'05-'064.6L Accepts Tremec TKO15255
Mustang'96-'044.6L/5.4L Accepts {{{Ford}}} Top Loader, Jerico DR-4 and Tremec TR3550/TKO w/7.{{{200}}}-in input shaft15230
Mustang'94-'95 5.0L V-8 Accepts factory BW T-5 transmission only15204
Mustang'83-'93289-302-351C/W Designed for factory cable-operated clutch. Accepts factory BW T-5 w/7.200-in input shaft15203
Mustang ’79-’93289-302-351C/W Designed for factory cable operated clutch. Accepts factory 4-speed (single rail overdrive),  
  Tremec TR3550/TKO and TR4250, Richmond 5/6 speed w/7.200-in input shaft15202
Mustang'79-'93289-302-351C/W Designed for factory cable operated clutch. Accepts Ford Top Loader/Ford BW T-10  
  w/1-1/16-10 spline and early Richmond five-speed15201