The old GM vehicles came with AC plugs and thats what I put in them. My Y-Blocks came with Champion so thats what I put in them. On the pickups I drive every day, I haven't changed plugs in 35 years. I trade every 3 years at about 50k miles and new plugs go longer than that with electronic ignition. I tell people if it ain't over 50 years old, I don't want to try to fix it except for 18 wheelers that put the bread on my table.