Manufactured by NGK SPARK PLUGS (6334)
Spark Plug — ZGR5C
uperior construction for serious power
Versatile plugs with wide operating heat ranges prevent fouling from running too cool and preignition from running too hot
Features high alumina ceramics for improved heat dissipation and electrical insulation, deep-seated copper core for a wider heat range and a nickel alloy tip for longer life
Below is a cross reference list of spark plugs for use in most Harley models. While the Motor Company only recommends use of their original equipment Harley brand spark plugs, the other brands often exceed original specification and will not void your warranty. NGK and Autolite, among others, have always been a preferred performance plug for Harley motorcycles. In addition, it is often more convenient to use aftermarket spark plugs aside from the enhanced performance. All spark plugs listed meet or exceed manufacturer specifications.

NOTE: Iridium plugs should only be used with electronic ignitions, not for use with point ignitions.

Shovelhead 1982-1984: H-D Standard 5RL / H-D Gold 5R6AG / H-D Platinum 5R6APP / Screamin’ Eagle SH13S / ACCEL 2417 / AC Delco 44NS/44XLS / Autolite 4285 / Bosch Platinum WR8DC4 / Champion RN13LYC / Denso Iridium IW16 / NGK ZGR5C (6334) / NGK Platinum BPR5EVX11 / Splitfire SF98E