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**Wrenchbender Ret** · 07-22-2018, 11:49 AM

The S type plugs (extended tip) came out in the 60,s & were an improvement over the regular plugs. Before long all the manufacturers switched to them. They actually run cooler then the old style plugs. The spark is closer in to the combustion chamber for faster combustion. It is best to use the S type like R43S or R44S. If an engine has the tapered seat use R44TS. The extended tip plugs cannot be used in flat head engines.

07-22-2018, 11:49 AM	#2
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,190	Re: What's the correct Spark Plugs? The S type plugs (extended tip) came out in the 60,s & were an improvement over the regular plugs. Before long all the manufacturers switched to them. They actually run cooler then the old style plugs. The spark is closer in to the combustion chamber for faster combustion. It is best to use the S type like R43S or R44S. If an engine has the tapered seat use R44TS. The extended tip plugs cannot be used in flat head engines.