Spec Clutch SF145 Stage 5 Race Clutch Kit - Full-Metallic Sintered Iron Disc

The Spec Clutch SF145 Stage 5 Clutch Kit is SPEC's most aggressive single-disc clutch offering, purpose-built for extreme drag racing, tractor pulling, and heavily modified performance engines demanding the absolute maximum in torque holding capacity. Rated up to 680 ft-lbs of torque, this kit is engineered for race-only environments where outright grip and durability outweigh drivability concerns.

At the heart of the Stage 5 is a full-metallic sintered iron disc delivering the highest possible friction coefficient in SPEC's clutch lineup. The solid, unsprung hub design uses a 12-rivet construction and is heat-treated for exceptional strength and long-term durability under race abuse. A high-clamp pressure plate provides aggressive engagement force to match the demands of extreme power levels. Note that because the hub is rigid with no springs to absorb drivetrain vibration, the harshness transfers directly to the transmission — this clutch is intended for dedicated race use.

What's Included:

• High-clamp pressure plate (adjustability available on select applications)
• Full-metallic sintered iron rigid disc assembly
• Throwout bearing
• Installation tool kit

Key Features:

• Full-metallic disc with maximum friction coefficient — top of SPEC's Stage lineup
• Solid 12-rivet heat-treated hub for superior strength and durability
• High-clamp pressure plate for maximum torque capacity up to 680 ft-lbs
• SFI approved for sanctioned racing applications
• Optional 26-spline disc hub available
• Compatible with billet flywheel replacement friction plate kit (with fasteners)

Intended Use: Drag racing, tractor pulling. Not recommended for street use due to harsh, aggressive engagement characteristics. Consult a SPEC technical representative to ensure proper configuration for your specific application.