ACT GM8-HDSS Heavy Duty Performance Street Sprung Clutch Kit for 1971–1974 Pontiac Firebird

GM8-HDSS kit features ACT's most popular Heavy Duty pressure plate and most popular street disc. ACT Heavy Duty pressure plates use exclusive diaphragm design to increase clamp load, reduce deflection and maximize clutch life. All diaphragms endure a four-stage, heat-treating process for unparalleled performance. ACT pressure plates have precision cover stampings to provide rigidity and consistency. ACT's Performance Street discs feature premium organic materials with high copper content for better heat transfer and steel-backed lining for greater burst strength and durability. These discs have reduced marcel for faster shift action to complement ACT pressure plates, with increased strength and reliability. HD/Perf Street Sprung Light to moderate pedal effort, smooth positive engagement, OE to mild gear rattle; Longer friction life, extended by ACT's exclusive diaphragm design; Carefully engineered, precisely assembled, accurately balanced, with premium organic friction materials for heat tolerance and reduced fade; Recommended for street and race use; 100% clamp load tested and dynamically computer balanced for smooth high RPM reliability

• "Excellence in Performance", backed by the best one-year warranty in the industry!

The ACT GM8-HDSS Heavy Duty Performance Street Sprung Clutch Kit combines a high-clamp-load pressure plate with a premium performance street disc for dependable engagement and long-lasting service. Designed for street and race applications, this kit delivers smooth, positive engagement with light to moderate pedal effort while supporting reliable power transfer in demanding driving conditions.

ACT Heavy Duty pressure plates use an exclusive diaphragm design to increase clamp load, reduce deflection, and help maximize clutch life. Each diaphragm undergoes a four-stage heat-treating process for consistent performance, while precision cover stampings improve rigidity and stability. The included Performance Street sprung disc uses premium organic friction material with high copper content for improved heat transfer, reduced fade, and extended friction life. Steel-backed lining enhances burst strength and durability, while reduced marcel promotes faster shift action and a positive pedal feel.

Every component is carefully engineered, precisely assembled, accurately balanced, and tested for dependable high-RPM operation. The GM8-HDSS kit is 100% clamp-load tested and dynamically computer balanced to help provide smooth, consistent performance. It is recommended for 1971–1974 Pontiac Firebird applications and is backed by ACT's one-year warranty. This automotive clutch kit is not intended for CARB-approved applications.

Product Specifications & Technical Data

• Brand: ACT
• Part Number: GM8-HDSS
• Clutch Type: Heavy Duty performance street sprung clutch kit
• Pressure Plate Design: Heavy Duty diaphragm pressure plate
• Disc Material: Premium organic friction material with high copper content
• Engagement Characteristics: Smooth, positive engagement with light to moderate pedal effort
• Application: Street and race use
• Testing and Balance: 100% clamp-load tested and dynamically computer balanced

What's Included

• ACT Heavy Duty pressure plate
• ACT Performance Street sprung clutch disc
• Clutch kit components required for the specified application

Features:

• Heavy Duty diaphragm pressure plate increases clamp load, reduces deflection, and helps maximize clutch life.
• Four-stage heat-treated diaphragm and precision cover stamping provide consistent performance, rigidity, and durability.
• Premium organic friction material with high copper content improves heat transfer and helps reduce fade during demanding use.
• Reduced-marcel sprung disc delivers faster shift action, smooth positive engagement, and light to moderate pedal effort.

Fitments:
1971 Pontiac Firebird Base
1972 Pontiac Firebird Base
1973 Pontiac Firebird Base
1974 Pontiac Firebird Base

Air Freight Prohibited: false
Not Carb Approved: false
Ltl Freight Required: false
Prop 65: Y
Part Type: automotive
Epa: N/A
Carb Acknowledgement Required: false
Regular Stock: false
Units Per Sku: 1