FASWORX Mercruiser Thunderbolt V8 Distributor Cap, Rotor & 8mm Spark Plug Wire Kit — 5.0/5.7/7.4/8.2/350, J1171 Brass Contacts

Complete distributor cap, rotor and 8mm spark plug wire kit engineered to restore reliable spark and ignition timing on Mercruiser V8 engines with Thunderbolt ignition systems.

This FASWORX kit supplies a new distributor cap, rotor and a full set of 8mm spark plug wires designed specifically for Mercruiser Thunderbolt-equipped V8 marine engines (5.0, 5.7, 7.4, 8.2, 350). Every component is sized and specified to match OEM fit and function, and the cap is J1171 certified with brass/copper contacts for consistent conductivity. The set includes installation hardware, a cap gasket and drain, and dielectric grease for the wire boots to simplify installation and help maintain corrosion resistance in a marine environment.

How does this kit improve ignition reliability on a Thunderbolt V8?

Replacing an aged distributor cap, rotor and wires removes wear-related resistance, carbon tracking and moisture paths that can cause misfires or weak spark. Fresh components restore tight connections and uniform spark distribution across cylinders, which helps the engine run more smoothly and start more predictably.

• J1171 certified distributor cap with brass/copper contacts for steady conductivity
• 8mm spark plug wires matched for consistent resistance and fit
• New rotor eliminates excessive air gap and wear at the contact point
• Included dielectric grease and gasket reduce moisture intrusion

Which Mercruiser engines and part numbers does this set replace?

This kit is made to fit Mercruiser V8 engines equipped with the Thunderbolt ignition system including 5.0, 5.7, 7.4, 8.2 and 350 CID models. It is a direct replacement for common OEM part numbers and aligns with Thunderbolt distributor configurations for those engines.

• Compatible with Thunderbolt ignition on 5.0, 5.7, 7.4, 8.2 and 350 V8 engines
• Replaces Mercruiser part numbers 805759Q3 and 84-816608Q61
• Designed for exact distributor cap mounting and rotor engagement
• Includes bolts, cap gasket, and drain for direct swap-out

What comes in the box and what tools or supplies will I need?

The box contains a new distributor cap, rotor, a full set of 8mm spark plug wires, mounting bolts, cap gasket, distributor drain and a tube of dielectric grease for the wire boots. You’ll need basic hand tools and a torque wrench if your engine manual specifies torque for cap bolts; a clean rag and small brush help with prep.

• Distributor cap and rotor sized for Thunderbolt distributors
• Set of eight 8mm spark plug wires with proper terminals
• Mounting bolts, cap gasket, distributor drain, and dielectric grease
• Recommended tools: ratchet, sockets, screwdrivers, and torque wrench

How should I maintain the ignition components after installation?

Periodic visual inspection and keeping connections clean and dry will extend service life. Reapply dielectric grease to boots when servicing and replace wires or cap at first sign of cracking, corrosion or carbon tracking.

• Inspect boots and cap seals for cracks or oil contamination
• Check for corrosion on brass/copper contacts and clean gently if needed
• Keep dielectric grease on boots to repel moisture and ease removal
• Follow engine manufacturer intervals for ignition system checks

Who is this for: marine owners, mechanics and restoration specialists working on Mercruiser Thunderbolt V8 engines who need a reliable, direct-replacement ignition kit. If you own a 5.0, 5.7, 7.4, 8.2 or 350 Mercruiser with Thunderbolt ignition and want OEM-style fit, J1171-certified cap contacts, and a complete set of 8mm plug wires with installation hardware, this FASWORX kit provides the parts and accessories required for a professional swap.