LS Engine to GM TH350/ 700R/200R4 Trans Kit

The LS Engine to GM TH350/700R/200R4 Trans Kit (MPN 712500A) is the definitive adapter solution for swapping modern LS powerplants into classic muscle cars, hot rods, and vintage trucks originally equipped with older GM automatics. This kit exists to bridge the gap between LS engine blocks and the three most common pre-overdrive transmission platforms, eliminating custom fabrication and ensuring repeatable, OEM-quality bolt-on fitment. Whether you're building a first-gen Camaro restomod, a fuel-injected C10 pickup, or a Fox-body Mustang with LS muscle, this adapter handles the mechanical interface that would otherwise require hours of machine work or expensive custom modifications.

This transmission adapter kit incorporates precision-machined aluminum construction designed to accept the bellhousing register of LS series engines while maintaining the correct spline alignment and mounting geometry for TH350, 700R4, or 200R4 transmissions. The adapter compensates for the dimensional differences in crank centerline height, bolt hole locations, and pilot bearing depth—critical factors that prevent driveline vibration, transmission binding, and premature bearing wear. Weighing just 7.52 pounds and measuring 15.3 x 2.4 x 15.3 inches, the kit ships complete with all necessary hardware and detailed fitment instructions, allowing experienced fabricators and mechanics to achieve a bulletproof LS swap without splicing together mismatched components or compromising structural integrity at the engine-to-trans interface.

This adapter is ideal for restorers and performance builders who demand reliability and correct geometry in high-horsepower LS conversions while retaining manual shifters, column shifts, or vintage console layouts tied to TH350 or 700R4 platforms. The 200R4 option adds overdrive efficiency for highway cruising without requiring modern six-speed transmissions, making it perfect for period-correct builds or budget-conscious swaps. Installation requires intermediate mechanical skill, familiarity with engine and transmission mounting procedures, and access to a lift or hoist; consult with your LS engine supplier regarding bellhousing selection, as some LS variants require specific adapter configurations. Verify transmission type and engine block generation before ordering to ensure seamless fitment.