Manufacturer Part Number AR3933X. Autolite Racing Spark Plugs are used by many professional race car drivers. These spark plugs contain an Yttrium-Enhanced Alloy, which enables up to 8 percent reduction in side wire temperature for improved durability and less pre-ignition.
These Autolite racing plugs have an advantage in design. the advantage is clearance, meaning they dont have a large ground strap to hit pistons when high lift cams and high compression pistons are used. this advantage makes for easier assembly , also with multiple angled ground straps an open spark will fire.