RPS Distributor Cap and Rotor Kit for Mercruiser V8 5.0–8.2L (Thunderbolt I & IV) with Gasket & Screws

RPS THUNDERBOLT Distributor Cap and rotor kit is a direct-fit replacement for Mercruiser V8 engines with Thunderbolt I and IV ignition, delivering the cap, rotor, gasket and mounting screws you need to restore reliable spark distribution.

This kit is made for GM-based Mercruiser V8 marine engines (5.0L, 5.7L, 7.4L, 8.2L) and fits the common OEM references 805759Q3, 805759T3 and 18-5935. It replaces worn or cracked distributor caps and aged rotors to help maintain consistent ignition timing and spark routing across all eight cylinders. Constructed with quality brass terminals in the cap and a precision-molded rotor, the set is designed to match factory fit and connector layout while offering an economical aftermarket option.

Will this kit fit my Mercruiser 5.7 V8 with Thunderbolt ignition?

Yes—this RPS kit is engineered to be compatible with GM-based Mercruiser V8 engines equipped with Thunderbolt I or IV systems. Check your engine’s part label or existing distributor for matching reference numbers to confirm fit.

• Compatible engines: 5.0L, 5.7L, 7.4L, 8.2L V8
• OEM references replaced: 805759Q3, 805759T3, 18-5935
• Fits Thunderbolt I and Thunderbolt IV ignition families
• Designed for GM-based Mercruiser distributors from early 1980s onward

What components are included and what materials are used?

The kit contains a distributor cap, a rotor, a gasket and the necessary screws for installation. The cap features brass terminal contacts for improved conductivity, while the rotor and housing use durable molded materials intended for marine engine environments.

• Distributor cap with brass terminals for reliable contact
• Molded rotor matched to factory dimensions
• Durable gasket to seal the distributor base
• Mounting screws included for a complete replacement

How straightforward is installation, and what should I prepare?

Installation is a straightforward swap if your distributor matches the listed references; the kit is designed for direct replacement with no modifications. Basic hand tools and a clean workspace are typically all that’s required—be sure to mark spark plug wire positions before removal to preserve firing order.

• Basic tools: screwdriver or small socket set
• Mark wire positions to maintain correct firing order
• Inspect rotor shaft and distributor cap seating for wear
• Follow engine service manual torque and alignment guidance

Why choose this aftermarket RPS kit instead of an OEM part?

This RPS kit targets the balance between factory-fit specifications and cost-effectiveness. It reproduces the essential fit and electrical interface of the original parts, while offering a lower price point and a ready-to-install package that includes the small hardware items often missing from partial replacements.

• OEM-compatible fit and electrical contact layout
• Includes cap, rotor, gasket and screws in one kit
• Cost-effective alternative to factory-priced components
• Designed for the common Thunderbolt ignition systems

Who is this for: The RPS THUNDERBOLT Distributor Cap and rotor kit is ideal for boat owners, marine technicians and DIY mechanics who run GM-based Mercruiser V8 engines with Thunderbolt ignition systems and need a full, direct-replacement cap-and-rotor assembly. If your distributor shows carbon tracking, cracked insulation, corroded terminals, or you’re following routine maintenance intervals, this kit provides the matching parts and hardware to return the ignition system to serviceable condition without resorting to expensive OEM-only purchases.