LS to TH400 Flexplate Kit – Gen III LS Engine to TH400 Transmission
This Advance Adapters LS to TH400 flexplate kit is engineered to adapt Gen III LS-series engines to GM TH400 automatic transmissions. Designed to address the unique crankshaft depth and bolt-pattern differences found in LS engines, this kit provides proper spacing, alignment, and durability for reliable drivetrain performance.
If you are installing a TH400 behind an LS engine, this LS flexplate TH400 solution delivers the correct components needed for a successful conversion.
Designed for Gen III LS Engines
All Gen III LS engines (4.8L, 5.3L, 5.7L LS1, 6.0L, and 6.2L) share a crankshaft design that differs from traditional small-block Chevy engines. The LS crankshaft sits 0.400 inches closer to the block and uses a unique bolt pattern, meaning only LS-specific flexplates will fit.
Key design considerations:
- Recessed LS crank flange (.400")
- Unique LS crank bolt pattern
- Standard small-block Chevy flexplates will not fit
This LS to TH400 flexplate is dished to compensate for the recessed crank while maintaining correct torque converter spacing.
How This LS Flexplate Adapts to the TH400
To properly mate a 4L60E or TH400-style torque converter to an LS engine, the following are required:
- A custom LS flexplate designed for TH400 compatibility
- A crank spacer to correct crankshaft depth
- Proper 11mm LS flexplate bolts
This kit includes all required components to ensure correct torque converter pilot depth, bolt alignment, and long-term reliability when pairing a TH400 transmission with an LS engine.
What’s Included
- Custom LS flexplate for TH400 / TH350 transmissions
- 11mm Gen III LS flexplate bolts
- Gen III LS crank spacer (bushing)
All components are precision-machined to OEM-quality standards.
Compatibility & Important Notes
Compatible with:
- Gen III LS engines with recessed crankshafts
- GM TH400 automatic transmissions
Not compatible with:
- LS7, LS9, LSA, or LSX engines (8-bolt crank)
- 2014 and newer Gen V engines (LT1, 4.3L V6, 5.3L, 6.2L)
- Certain 6.0L engines with cast-iron cylinder heads and non-recessed crank
- 1999–2003 4.8L engines originally paired only with manual transmissions
Always verify crankshaft configuration before ordering.
Why Choose Advance Adapters LS to TH400 Flexplate?
- Purpose-built LS flexplate TH400 solution
- Corrects LS crankshaft depth differences
- Ensures proper torque converter alignment
- Manufactured from premium materials
- Designed by drivetrain conversion specialists
Bill of Materials
- 716141A – Gen III LS 11mm flywheel bolts
- 711500A4 – LS engine to TH400 / TH350 flexplate
- 716155A – Gen III crank spacer bushing
Bill Of Materials
