Autolite Spark Plug, AR51 (FF1600)

The Autolite AR51 spark plug has a 14 x 1.25mm thread and 0.75" reach. The cut-back ground electrode offers maximum spark exposure for improved performance. The AR51 is considered a hot plug for most 4-stroke water-cooled automotive engines.

This is a standard spark plug for Formula Ford 1600 (Ford Kent & "Uprated") engines running the original iron cylinder head. The 13/16" hex works well in the original cast iron head on the FF1600 engine, but it is very tight in the SCCA aluminum head. Interchangeable with Champion N6YC.

Spark plugs are sold individually.