All plugs are, But you should check them yourself again.
From what I've been told from my AC DELCO REP they are NGK plugs
ac delco copper Use the factory recommended plugs. AC delco 41906.
AC Delco Iridium spark plugs.
Spark Plugs .035Points .019Plugs--AC/Delco R43N
AC/Delco
AC-Delco.
ac delco
I would recommend the OEM spark plugs, AC/Delco. Excellent plugs.
AC Delco
I suggest you install OEM AC/Delco plugs.
AC/Delco
AC Delco Iridiums