Upgrade your Full Size Jeep with this precision-engineered GM automatic transmission adapter kit, designed for seamless swaps with AMC 4.2L 6-cylinder engines. This kit enables you to run a wide range of GM automatics—including TH350, TH400, TH700R4, early 4L60E, and 4L80E transmissions (with proper torque converter and controller)—while retaining reliability and stock fitment.

The kit features a robust, 0.5-inch laser-cut, Blanchard-ground steel adapter plate, CNC-machined with CMM-mapped dowel locators for exact alignment. The included 164-tooth modified flexplate is built for lasting performance and is compatible with both Chevy and Buick/Olds/Pontiac (B/O/P) style engine flanges.

Transmission Compatibility Notes:

• 4L80E: Fully compatible when using a modified factory 4L80E torque converter with the TH350 bolt pattern, plus a standalone transmission controller.
• Early 4L60E/4L80E: Require a separate, standalone transmission control unit.
• Late 4L60E/4L80E (removable bellhousing/hex rear pattern): Not compatible with this kit.
• TH350: The only suitable choice for 1972–1983 CJ5 Jeeps due to length; avoid excessive lifts for proper driveline angles.
• 6L80E: Not compatible.
• TH400: Must use the smaller 9-3/8” torque converter bolt pattern (for TH350, TH400, 700R4); not compatible with the larger 10” pattern.
• AMC Starters: Works with AMC starters; some applications require a different starter—see instructions for specifics.
• Pre-1971 AMC engines: Please contact us before ordering to confirm correct crankshaft spacer requirements.

Kit Contents:

• Zinc-plated adapter
• Flexplate
• Flexplate reinforcement ring
• Flexplate spacers
• Dowel locators
• Crank spacer
• Shield plate with access port for torque converter bolts
• Hardware
• Detailed installation instructions

Fits:

• All FSJs with 4.2L Engine