Motorcraft SP-429 Spark Plug Fits select: 1984-1986 FORD LTD, 1984-1986 FORD MUSTANG

The only parts recommended by Ford Motor Company for Ford, Lincoln, and Mercury vehicles.Same spark plugs that were installed when the engine left the assembly line, Spark plugs are matched to the engine for optimum engine performance. Spark plug designs include continuous improvements, Resist oxidation and arc erosion, Multi-rib insulator protects against misfire, Nickel-plated shell for corrosion resistance (on all except Standard Copper Core), High-Strength Steel High Thread, Platinum-Iridium, and Fine-Wire Double-Platinum feature 0.8 mm fine-wire design.Fine-Wire Double Platinum features Platinum pad on both electrodes. Extended service intervals (on all except Nickel and Standard Copper Core plugs), Proprietary platinum pad on side wire electrode (on Platinum-Iridium and Fine-Wire Double Platinum plugs). Platinum-Iridium plugs feature Iridium-enhanced center electrode. Platinum-Iridium plugs can be used in any engine regardless of ignition system.High-Strength Steel High Thread spark plugs for 3-valve Triton engines redesigned: New, high-strength steel shell, Nickel-plated shell for corrosion resistance, Scavenger area allows for more carbon build-up before misfires occur, Full ground strap helps for better heat transfer within the combustion chamber, Thicker insulator for better misfire prevention.Long Service Intervals: 100,000 mile service interval, High-Strength Steel High Thread, Platinum-Iridium, Fine-Wire Double Platinum, 60,000-100,000 mile service interval, Up to 60,000 mile service interval: Nickel, Standard Copper Core.