Sierra 18-5470 Thunderbolt IV HEI Marine Distributor GM V-8 MerCruiser

The Sierra 18-5470 Thunderbolt IV V-8 Distributor is a high-quality marine ignition distributor engineered as a direct replacement for Mercury Thunderbolt IV ignition distributors on GM V-8 marine engines. Built to Sierra's exacting standards, this HEI (High Energy Ignition) distributor delivers reliable spark delivery and precise ignition timing for dependable on-water performance.

Key Features:

• Battery Powered HEI (High Energy Ignition) — provides strong, consistent spark for reliable engine starts and smooth operation
• Hall-Effect type sensor — triggers ignition accurately even at extremely low RPM for superior low-speed performance
• Direct replacement for Mercury Thunderbolt IV ignition distributors
• Meets or exceeds SAE J1171 standards for marine ignition components
• Compatible with GM V-8 engines equipped with Thunderbolt IV & V ignition systems

Replaces & Interchangeable With:

• Mercury / MerCruiser: 805185A37, 805185A36, 805185A26, 805185A16, 805185A6, 805185A43, 90747A27

Note: Distributor does not include ignition module. Sold individually.