Spec Clutch SB665 Stage 5 Performance Clutch Kit - Full-Metallic Sintered Iron

The Spec Clutch SB665 Stage 5 Clutch Kit is SPEC's highest-performance single-disc clutch solution, engineered for extreme motorsport applications including drag racing, pulling competitions, and high-output modified engines. Built around a full-metallic sintered iron disc, the Stage 5 delivers the highest possible friction coefficient available in the SPEC lineup for maximum torque transfer and aggressive engagement.

The disc assembly features a solid 12-rivet unsprung hub that is heat-treated for superior strength and durability under extreme loads. A high-clamp pressure plate ensures consistent clamping force even under the most demanding race conditions. While technically street-drivable, the Stage 5's rigid disc construction and instantaneous engagement characteristics make it unsuitable for regular street use — this is a purpose-built race clutch.

Key Features:

• Full-metallic sintered iron friction disc with maximum friction coefficient
• High-clamp pressure plate for maximum torque clamping force
• Solid 12-rivet unsprung hub — rigid, instantaneous engagement
• Heat-treated disc assembly for long-term strength and durability
• Includes bearing and tool kit (select applications)
• Ideal for drag racing, pulling, and autocross
• Street-drivable, but not street-friendly — not recommended for daily use

Important Break-In Notice: A minimum 450-mile break-in period consisting primarily of city and stop-and-go driving is required before full-throttle engagement, drag launches, or speed shifting. The existing flywheel must be properly resurfaced prior to installation unless a new SPEC flywheel is being used. Failure to follow break-in and installation procedures will void the warranty.

Intended Use: Drag Racing, Pulling, Autocross, Extreme Performance Street