Sierra 18-5476 Delco EST HEI Marine Distributor for GM V6 Engines

The Sierra 18-5476 is a marine-grade Delco EST (Electronic Spark Timing) HEI distributor engineered as a direct replacement for GM V-6 inboard and sterndrive engines. Replacing Mercury Marine OEM part number 807964A1, this distributor is built to meet or exceed the demands of the marine environment while delivering reliable ignition performance.

Sierra designed this unit to fit 1996 and newer GM V-6 engines equipped with a Delco EST HEI ignition system, making it a straightforward, bolt-in solution for restoring proper spark timing to your vessel's powerplant. The aluminum housing replaces the weaker factory plastic housing for improved durability in harsh marine conditions.

Key Features:

• Direct replacement for late-model GM EST (Electronic Spark Timing) distributor
• Fits GM V-6 engines with Delco EST ignition HEI (1996 and up)
• Aluminum housing construction for superior corrosion resistance
• Reliable high signal strength magnetic trigger system
• Ball bearing and bushing combination for maximum timing stability and long service life
• Includes steel distributor gear compatible with flat tappet or hydraulic roller cams
• Includes distributor cap (18-5362), ignition module (18-5107-1), and rotor (18-5408)
• Meets or exceeds SAE J1171 marine ignition standards
• Replaces Mercury Marine OEM #807964A1
• 1-year limited warranty

The Sierra 18-5476 comes as a complete assembly with distributor cap, rotor, and ignition module included—everything needed for a full ignition distributor replacement. Whether performing routine maintenance or troubleshooting a no-start condition, this Sierra distributor is a trusted OEM-quality solution for GM V-6 marine applications.

OEM Cross-Reference: Mercury Marine 807964A1 | Sierra MPN: 18-5476 / 118-5476