They're Autolite Spark Plugs: AL104s

you kouldnt pay me to put autolites in anything i own, i'll stick with AC Delco Pro Platinum Iridium plugs, even tho they are 42 bux a set, the difference is noticeable, i know, ive been there, my old GTP had autolites, and was a turd, after some AC Low resistance wires and pro platinums it made a HUGE difference both power and mileage and no i dont wanna argue

That's okay, I was just answering your question. I use AC Delco Iridium plugs, and AC Delco ignition wires on my GP. Works just fine for me!

Unless your modded, you'd better be running 606s (stock) or 605s. Only people with a good amount of mods need to runs 104s and 103s. I could even get by on 104s.