Iridium Spark Plug 1IR4Y Resistor Type with Projected Tip Tapered Seat. 14mm x .691" with 5/8" Hex

MSD’s spark plugs are engineered to improve the efficiency of the combustion process to create the most power possible combined with increased durability. The center tip of the plug is madefrom iridium to promote the best spark and increase resilience. A proprietary ceramic material enhances the dielectric strength of the plug housing forcing the spark, even under extreme cylinder pressures, to jump across the plug gap to the ground electrode. This electrode is machined to expose more spark to the incoming gases to promote the most effective combustion event possible.

• Proprietary plug design insideand out
• Designed for use on high performance vehicles that utilize high output ignition systems
• Machined electrode increases exposure to the flame to improve combustion
• MSD’s proprietary ceramic formula provides the highest dielectric strength
• Yttrium ground electrode reduces the chance of pre-ignition
• Iridium tip improves cold starts
• Designed to outlast other performance plugs on the track or on the street
• All spark plugstested prior to packaging and shipping
• Shorty-style plugs for applications where space is limited

What makesMSD’s Iridium plugs a cut above the competition? BesidesMSD's race winning experience of firing 330 mph top fuel cars, the endurance of 500 mile stock car racing and the brutal expectations of off-road racing, our new sparkplugs are designed to perform from the inside out.