Spec Clutch SZ374 Stage 4 Carbon Puck Clutch Kit

The Spec Clutch SZ374 Stage 4 Clutch Kit is a race-grade, solid-hub performance clutch engineered for heavily modified engines demanding maximum torque capacity and instantaneous engagement. Built as a solid hub evolution of the Stage 3, this kit is purpose-built for competition use in drag racing, road racing, drifting, rally, pulling, and circle track applications.

Solid Hub Construction: The Stage 4 features a solid 8-rivet hub design with a heat-treated disc and carrier assembly for enhanced strength and durability under extreme load conditions. The rigid hub delivers aggressive, direct power transfer — ideal for race environments where every millisecond of engagement matters.

Puck Configuration Options: The SZ374 is available in 3, 4, or 6-puck carbon semi-metallic friction disc configurations to match your specific racing needs:

• 3-Puck: Lightest rotating mass — ideal for high-revving race applications
• 4-Puck: Balanced compromise between weight and engagement smoothness
• 6-Puck: Smoothest engagement of the three options; marginally street-drivable, though not recommended for daily use due to the rigid hub

Key Features:

• High-clamp performance pressure plate for maximum clamping force
• Carbon semi-metallic friction material for aggressive grip and heat resistance
• High-torque solid 8-rivet hub and disc assembly, heat-treated for durability
• 9.500 in. (241 mm) disc diameter
• 23-spline input shaft, 1.031 in. shaft diameter
• Torque rating: up to 207 ft/lbs
• SFI approved
• Includes release bearing and installation tool kit
• Sold as a complete kit (flywheel not included)

Recommended Applications: Drag Racing, Road Racing, Drifting, Rally, Pulling, Circle Track. Not recommended for street use due to the rigid hub and harsh engagement characteristics inherent to a Stage 4 race clutch.