SFI Flexplate GM LSA Engine

The TCI SFI Flexplate GM LSA Engine (part number 399756) is a 168-tooth flexplate engineered specifically for GM LS-series engine swaps requiring SFI 29.1 certification. This internally balanced steel flexplate bridges the engine to the transmission in high-performance builds where regulatory compliance and durability are non-negotiable. The SFI 29.1 rating means this component has passed rigorous safety testing for motorsports and street applications, making it essential for any LS-swap project intended for serious track use or competition duty.

The 168-tooth design matches standard LS-series bellhousing geometry and torque converter configurations. Internal balance means the flexplate's weight distribution is optimized to work seamlessly with internally balanced LS engines—a critical detail that prevents vibration and premature wear of the crankshaft nose, transmission input shaft, and torque converter. Steel construction provides the strength necessary to handle sustained power transfer in high-revving applications. At 9.8 pounds, this component carries the mass required for reliable power delivery without unnecessary weight penalty that would affect engine balance or overall drivetrain responsiveness.

This flexplate is intended for builders performing LS-engine conversions into non-original platforms, restomods, and performance vehicles where OEM solutions don't apply. Whether swapping an LS into a classic muscle car, street rod, or modern chassis requiring bolt-on power, an SFI-certified flexplate protects both the installation and the builder's liability. The SFI 29.1 certification is recognized across sanctioned racing organizations and demonstrates that TCI has engineered this component to withstand the extreme demands of forced-induction, high-RPM, and high-torque environments that typical street flexplates cannot reliably handle.