Spec Clutch SD413F Stage 3+ High-Performance Clutch Kit

The Spec Clutch SD413F Stage 3 Plus (Stage 3+) is the flagship single-disc clutch kit for heavily modified street and race vehicles that demand maximum torque capacity with a manageable, driver-friendly engagement. Designed for builds that have outgrown the standard Stage 3, this kit steps up holding power while maintaining better daily drivability and superior wear characteristics compared to more aggressive race-only options.

At the heart of the Stage 3+ is a full-faced carbon semi-metallic friction disc — a material chosen for its outstanding balance of friction coefficient, service life, and consistent engagement feel. The disc uses a double-sprung hub with spring cover reliefs for added flexibility under load, and all hub components are heat-treated for long-term strength and durability.

Kit Includes:

• High-clamp performance pressure plate
• Full-faced carbon semi-metallic friction disc
• High-torque double-sprung hub and disc assembly
• Release bearing
• Installation tool kit

Ideal Driving Applications:

• Street / Daily Driving
• Drag Racing
• Drift
• Road Racing
• Autocross
• Rallye
• Pulling

Every Spec Clutch kit is designed, hand-built, and tested in the U.S.A. at their purpose-built facility in Bessemer, Alabama. Spec engineers each stage to deliver the optimal combination of clamp load, friction material, disc diameter, and rotating mass for the intended use — ensuring reliable, repeatable performance whether on the street or the strip.