MSD 8225 HEI Ignition Coil GM HEI Distributor Replacement

The MSD 8225 is a high-performance ignition coil engineered as a direct drop-in replacement for the stock coil in GM HEI coil-in-cap distributors. Featuring a 70:1 turns ratio and low primary resistance, this coil delivers a significantly stronger voltage output than the factory unit, improving combustion efficiency and engine response.

The MSD 8225 is compatible with stock HEI ignition modules, but is optimized for use with the MSD High Output HEI Module (PN 8364 / PN 83647) for maximum spark energy. When paired with the MSD HEI Module, it delivers full-power sparks all the way to 9,000 RPM — making it an excellent choice for both street and performance builds. The epoxy-filled construction ensures long-lasting durability in demanding environments.

Key Features:

• Direct performance replacement for GM HEI coil-in-cap distributors
• 70:1 turns ratio for high voltage output
• Maximum voltage output: 42,000 volts
• Primary resistance: 0.31 ohms
• Secondary resistance: 9.2K ohms
• Inductance: 3.5 mH
• Peak current: 200 mA
• Spark duration: 200 µS
• Full power sparks to 9,000 RPM when used with MSD HEI Module PN 8364/83647
• Epoxy-filled internal construction for durability
• CARB E.O. Approved (E.O. #D-40-37) — legal for sale and use in all 50 states

The MSD 8225 installs directly into the factory location using the OEM connector, making installation straightforward and hassle-free. For maximum ignition performance, pair with the MSD High Output HEI Module PN 8364.