Spec Clutch SF64S Billet Steel Flywheel SFI Certified - 1.1 164-Tooth 6-Bolt

The Spec Clutch SF64S is a high-carbon billet steel flywheel CNC-machined to an industry-leading .001-inch tolerance — ten times tighter than the standard .010 tolerance found across the industry. This exceptional precision ensures perfect rotational balance and a perfectly flat friction surface, reducing vibration, protecting engine components, and maximizing clutch performance and longevity.

Featuring a 164-tooth ring gear and a 6-bolt crankshaft pattern, the SF64S accepts both 10.5-inch and 11-inch clutch diameters thanks to its dual bolt and dowel pattern. The friction surface is made from a specially formulated high-carbon steel alloy engineered to promote superior clutch disc bedding and holding power.

Key Features:

• CNC-machined from high-carbon billet steel to .001-inch tolerance for perfect balance and surface flatness
• Rebuildable design with a replaceable steel friction plate — extends service life and protects your investment
• Dual bolt/dowel pattern — compatible with both 10.5-inch and 11-inch clutch assemblies
• 164-tooth ring gear with 6-bolt crankshaft attachment
• SFI 1.1 Certified — meets safety standards required for sanctioned racing and high-performance competition environments
• Optimized moment of inertia (MOI) for improved throttle response and power transfer
• Manufactured in the USA

The SF64S is engineered to deliver the precise inertia characteristics needed for performance street and competition use. Unlike cast OEM flywheels, SPEC's billet steel construction eliminates dimensional runout that causes power-robbing vibrations and premature clutch wear. The SFI 1.1 certification makes this flywheel track-legal for NHRA, IHRA, and other sanctioning bodies requiring certified rotating components.