The AC Delco plug # 41-993 that the 4.3 engines call for used to be the Professional Double Platinum right? I just bought a new set and the box now says Professional Iridium. Same part number & still around the same price ($5.00). Wonder what happened to the Double Platinums?

 

Most likely GM's marketing department thought the new name sounded better. Next up is you only get 5 plugs for the old price of 6...just like a half gallon of ice cream is now 48 onces and a pound of coffee is 13.8 onces.

 

I don't know about the box they were in, but acdelco.com still lists #41-993 as 'platinum'.

 

It still lists them as platinum everywhere else too. Got them from RockAuto which has them as platinum as well.

I'm going to send an email to AC Delco & see what they say.