For bolt on naturally aspirated and mildly modified forced induction engines. Stock-like daily drivability and very good wear characteristics.
High clamp pressure plate, steel-backed and multi-compound woven organic material and high torque sprung hub and disc assembly, bearing and tool kit.

For all mild to moderately modified naturally aspirated and power adder engines. Also good for stock power levels and spririted driving when good daily drivability and extremely long life are the goal. Stock-like daily drivability and excellent wear characteristics.
Includes high clamp pressure plate, pure Kevlar friction material and high torque sprung hub and disc assembly, bearing and tool kit.

SPEC Stage 2+ Clutch Kit for 1996-2001 Mustang Cobra.
For all modified engines making more torque than the Stage 2 can support. Maintains Stage 2 feel for good daily drivability and offers very good wear characteristics, but provides a higher torque capacity.
Includes high clamp pressure plate, composite multi-friction carbon-Kevlar material, high torque sprung hub and disc assembly, bearing and tool kit.

For heavily modified street and race engines. Offers sufficient daily drivability with a comfortable pedal feel and quick engagement. Offers good wear characteristics under low and high stress usage.
High clamp pressure plate, 4 or 6 puck carbon semi-metallic friction with high torque sprung hub and disc assembly, bearing and tool kit. 6 puck is standard on most applications, but 4 puck can be specified when ordering.

For heavily modified street and race engines making more torque than the st3 can support. Offers good daily drivability and better manageability than the stage 3, with even better wear characteristics.
High clamp pressure plate, full-faced carbon metallic friction, high torque sprung hub and disc assembly, bearing and tool kit.

For heavily modified engines or engines of any modification level being used in the above driving environments, where an instantaneous engagement and light weight are beneficial. Not street-friendly due to harsh engagement.
High clamp pressure plate, 3,4 or 6 puck carbon semi-metallic friction with high torque rigid hub and carrier assembly, bearing and tool kit.

For extremely modified drag race and pulling engines, or applications that call for a slipper clutch/progressive torque-induced engagement. These clutches are best ordered as custom configured and should be ordered after providing specific information about the car and it’s purpose to a SPEC technical assistant. Not street-friendly due to harsh engagement.
High clamp pressure plate (adjustability available on some applications), rigid iron disc assembly, bearing and tool kit.

Firstly, the flywheel should provide a consistent and friction enhancing surface for the clutch disc.
Flywheels also aid in proper inertia, which is determined by the flywheel weight. Inertia controls the ratio of power to acceleration and can make a vehicle faster or slower based on gear ratio, tire type, vehicle weight, power output and even the location in the powerband output is achieved. The weight of a flywheel and amount of inertia it provides can also effect drivability.
Lastly, the flywheel must provide a true balance at rpm, which means no dimensional runout that produces engine damaging and power robbing vibrations and allows smooth engine revolutions.

SPEC flywheels are CNC manufactured at an unheard-of .001 tolerance, in an industry where the standard is .010. This precision manufacturing process ensures perfect balance and a perfectly flat bedding surface for the clutch disc, both of which also contribute to the ultimate in safety for competitive environments. All SPEC flywheels carry SFI certification. (sfi link)

To allow for specific inertia needs, SPEC flywheels are made in high carbon billet steel and aircraft quality billet aluminum. The aluminum and most steel SPEC units are rebuildable and feature a replaceable steel friction plate that is made from a friction- enhancing steel metal specially formulated for optimum clutch bedding and holding power. The aluminum and steel materials provide a light and medium weight option for all types of racing. SPEC spends a lot of time and effort on research and development of optimum flywheel dimensions and weights for all types of driving and racing and can optimize your MOI (moment of inertia) to maximize your car's output and performance.

SPEC Aluminum Pressure Plate for 1996-2001 Ford Mustang GT Part# SF48APP