Distributor Cap Rotor Kit Tune-Up Kit For Marinized GM V-8 engines with Thunderbolt IV & V HEI ignitions 5.0L 5.7L 7.4L 8.2L 805759Q3 805759T3 18-5273 Application: For Marinized V-8 308, 350, 454, 502 Engines made by For General Motors with Thunderbolt IV and V HEI Ignition Systems. Only works with HEI (High Energy Ignition) Systems and will NOT work with Point Ignition Systems! Fit below Engines: 5.0L V8. 5.7L V8 (Inc 350 MAG). MX 6.2L V8. 7.4L V8 (Inc 454 MAG). 8.2L V8 (Inc 502 MAG). Vehicle compatibility charts are for REFERENCE ONLY. Please Check your vehicle with OEM below to match your needs. Also check product type and size. 805759Q3, 805759T3, 18-5273, 71780. 9-29350, 64759K, RL5273, 18-5710, 18-5395, 18-5431, 18-5723, 18-5935. Specification: 100% quality aurance tested, more responsive, le expensive, easier to install. Meet original equipment manufacturer specifications to best protect your engine. Good strength, stiffne and resistance to warpage, resistance to thermal cracking. Solid bra inserts resist corrosion and electrical pitting for long service life. Resist RFI (Radio frequency interference) interference with onboard electronics. Material & Color: Material: made of high quality Metal & Bra & PP. Color: as picture. Package Included: 1x Distributor Cap (18-5395); 1x Rotor (18-5431); 1x Gasket; 1x Fitting; 4x Screw. (100% Brand New Never Used Or Installed) What is a distributor cap and rotor? Distributor caps and rotors areresponsible for paing the voltage from the ignition coils to the engine's cylinders in order to ignite the fuel-air mixture inside and power the engine. The coil connects directly to the rotor, and the rotor spins inside the distributor cap. The distributor distributes the high voltage spark from the coil to the correct cylinder required. Eventually they wear out over time like the spark plugs and wires resulting to poor electrical insulation which causes engine problems in the future therefore making it important to be part of the regular tune-up maintenance. 6 Symptoms of a Bad Distributor 1) Your engine keeps misfiring or backfiring. 2) Your boat hard start or losing power. 3) Your boat is running erratically. 4) You hear a high-pitched noise coming from engine. 5) Your check engine light comes on. 6) You failed your last emiions test. Note: Provide Tracking Number With Every Order, Please Buy With Confidence! No installation guides are included, we highly recommend to seek profeional installation. Any damage during installation will not be refunded. Will come with everything you see in the picture. Please allow difference due to manual measurement. Please check that the picture matches before purchase. The color of the actual items may slightly different from the listing images due to different computer screen, thanks for your understanding. For any inquiries or special requests such as larger amount ordering please write to us.