MSD® GM/Ford Iridium .691" Spark Plug
MSD® GM/Ford Iridium .691" Spark Plug
MSD® GM/Ford Iridium .691" Spark Plug


MSD® GM/Ford Iridium .691" Spark Plug

Regular price$34.95
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Compatible: (3.8L/4.0L/4.6L/4.8L/5.0L5.3L/5.7L/6.0L)

2004 - 2007 Cadillac CTS-V

1993 - 2002 Chevy Camaro

1992 - 2008 Chevy Corvette

1999 - 2006 Chevy Silverado

1999 - 2006 GMC Yukon

1993 - 2002 Pontiac Firebird 

2004 - 2007 Pontiac GTO

1979 - 2004 Ford Mustang

2001 - 2005 Ford Focus

This part is legal for sale and use on Emissions Controlled Vehicles when used in accordance with the manufacturers application guide because it is a direct or consolidated replacement part.

The following vehicles are considered Emissions Controlled Vehicles:

  • 1966 and newer U.S. manufactured California Certified vehicles
  • 1968 and newer U.S. manufactured Federally Certified vehicles
  • 1968 and newer Foreign manufactured vehicle



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 made from 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 inside and 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
  • All spark plugs tested prior to packaging and shipping
  • Unique insulator design improves spark isolation
  • Lower voltage Requirements for longer coil life

Brand MSD
Emission Code 2
Heat Range 5
Hex Size 5/8
Length Standard
Plug Style Code 1IR5Y
Product Type Spark Plug
Projected Tip Yes
Quantity 4
Reach 0.6910
Resistor Yes
Seat Type Tapered
Style Iridium
Thread Size 14mm
Warranty Limited 1 Year Warranty
Part Number 37134