A new 14 mm automotive spark plug, called the Fire Ring II, was introduced in the new 1967 Buick 400 and 430 cu in. engines.
This new development provides the engine designer with greater latitude in three fundamental areas: spark gap location, spark plug cooling, and spark plug accessibility.
The spark plug combines a 5/8 in. hex and a 63 deg conical seating arrangement with the popular 14 mm thread to provide a reduction in overall size. The smaller [illegible] space required offers the engine designer [illegible] more flexibility in spark plug positioning.
Extensive laboratory and vehicle testing [illegible] the new spark plug will perform all required [illegible].
