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.