Meet specifications to protect your engine. Good strength, stiffness, warping resistance and hot cracking resistance.Solid brass inserts are resistant to corrosion and pitting and have a long service lifeResist RFI (radio frequency interference) interference to on-board electronic equipment.Part Number: 187523 805759Q3 815407A2 18-5395 805759T3 805759T1 13524T1 18-5273 13524A5 16457A4 805759T2 805759A1Applicable model: Applicable to Marinated V-8 308, 350, 454, 502 Engines make by For with IV and V HEI Ignition Systems. Only for HEI (high energy ignition) system, not for point ignition system Installed under the engine:5.0L V8.5.7L V8 (Inc 350 ).MX 6.2L V8.7.4L V8 (Inc 454 ).8.2L V8 (Inc 502 ).What are distributor covers and rotors?The distributor cover and rotor are responsible for transmitting voltage from the ignition coil to the engine cylinder to ignite the internal fuel mixture and supply to the engine. The coil is directly connected to the rotor, which rotates in the distributor cover.The distributor distributes the high-pressure spark in the coil to the correct cylinder as required. Over time, they will eventually wear like spark plugs and wires, resulting in poor electrical insulation, which will lead to engine problems. Therefore, they are very important as part of regular adjustment and maintenance.6 Symptoms of a bad distributor1) Your engine has been misfiring or backfiring.2) Your has difficulty starting or loses .3) Your is unstable.4) You hear a loud noise from the engine.5) Your check engine indicator illuminates.6) Your last emission test failed.color:BlackMaterial:MetalPackage Contents:1 x Distributor Cap KitOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.