Mopar 8-Bolt Gen-3 Hemi to GM - Flexplate

The Mopar 8-Bolt Gen-3 Hemi to GM Flexplate by J-W PERFORMANCE is a precision engine adapter engineered for builders swapping a Mopar Gen-3 Hemi engine into a GM vehicle platform. This flexplate serves as the critical mechanical bridge between your Hemi's crankshaft flange and a GM automatic transmission, enabling modern Hemi power in classic or contemporary GM chassis. Whether you're building a restomod, upgrading a truck, or executing a full powertrain conversion, this adapter eliminates guesswork and ensures proper bolt-pattern alignment without costly machine work or custom fabrication.

J-W PERFORMANCE's design accommodates the Mopar 8-bolt crankshaft configuration while maintaining full compatibility with GM flexplate bolt patterns and torque converter seat geometry. The 8.16 lb weight reflects a cast-iron or ductile-iron construction that withstands the torsional loads inherent to high-output Hemi engines without flex or deflection. Precision machining ensures concentricity between the crank flange and transmission interface, preventing vibration, converter runout, and premature seal wear. The adapter's durability under sustained boost, nitrous, or stroker applications makes it a trusted choice for serious engine swaps where reliability cannot be compromised.

This flexplate is ideal for enthusiasts and professional shops performing Hemi-into-GM conversions on Chevrolet, GMC, or Pontiac vehicles with matching transmission pads and bolt configurations. Proper installation requires careful alignment and torque sequencing to OEM specifications; verify your transmission type and flexplate bolt count before ordering to confirm compatibility. The adapter's compact 14.75 x 15.1 inch footprint fits within standard engine bay dimensions, though tight clearances may require minor pan or header modifications on some platforms. Quality engine mounts, custom header work, and fuel system integration are typical alongside this adapter in a complete conversion package.