
399754 SFI-Approved Flexplate LS1/LS2/LS6/LS7 to 4L80-E Transmission
- .067" thicker than stock
- Made from A36 steel plate
This flexplate is designed for use when bolting a GM LS-based motor to a 4L80E and utilizes the 6-bolt mounting pattern. This flexplate is dual-drilled with the 11.50 in. and the 11.063 in. bolt pattern. This will not fit 1999-2000 6.0L applications with 0.400 in. extended crank flange and came with flat flexplate. This will not fit 1999-2000 4.8L applications that originally came with a manual transmission.
SFI-Approved Racing Flexplates
TCI Heavy-Duty Flexplates are .0350 in. thicker than stock plates in order to withstand the stress of high-RPM engines and high-stall torque converters. Chevy 168-tooth plates have dual bolt patterns to accommodate both Powerglide and Turbo-Hydramatic (TH) torque converters. TCI also offers externally-balanced Small Block Ford to GM Transmission Adapter Flexplates that feature a built-in pilot adapter and a dual bolt pattern for a simple bolt-on installation. Note: For use with a racing converter or GM Powerglide adapter.
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When your build demands strength, durability, and reliable performance under fire, the TCI Heavy-Duty Flexplates deliver exactly that. These heavy-duty components are built to last, especially for high-stall torque converters and high-RPM engines.
TCI flexplate models are thicker than stock—specifically .0350 inches extra—to resist warping, cracking, or damaging deflection when torque and revs rise. Chevy 168-tooth plates in this line feature dual bolt patterns so they work with both Powerglide and Turbo-Hydramatic transmissions. These plates are precision engineered to maintain alignment, retain structural integrity, and handle the stresses OEM parts can’t reliably overcome.
If you’re running an LS swap or high output small block, a TCI LS1 Flexplate option gives you a bolt-on upgrade with improved durability, especially if you’ve upgraded torque converter size, stall speed, or intend to push rev limits. Compatibility across various bolt patterns, balanced designs, and high-quality materials mean you can upgrade without compromising fitment or strength.
A chevy flex plate from this line isn’t just about brute force—it’s about maintaining reliability under load. Proper flexplate selection protects your torque converter, starter, crank flange, and ultimately your transmission. Whether for racing, high performance street, or demanding duty, using a heavy-duty version pays in longer life, fewer failures, and cleaner engagement. Add a Heavy-Duty Flexplate to your setup to get the peace of mind and performance your drivetrain deserves.


![Heavy-Duty SFI Flexplate for 1997-2016 GM LS1, LS2, LS6 Series Engines [Internally Balanced]](https://www.jegs.com/images/mini_200/500/555/555-601080.jpg)






![Flexplate [GM LS Engine]](https://www.jegs.com/images/mini_200/800/809/809-19260102.jpg)

