Icing on the cake They are the icing on the cake in a modified engine (excluding ignition mods). These plugs are especially good in an engine that doesn’t have a centered in combustion chamber plug or dual plugged head. Jeff B., Verified Buyer Spark Plugs 5 2020-01-03T21:36:25+00:00 Jeff B., Verified Buyer They are the icing … Continue reading Icing on the cake