I had been running NGK Iridium for about a year. Somehow, it just felt the car ran smoother when I ran old non-platinum Rapidfire 5s.
So, I ordered 8 new platinum tipped Rapidfire 5s from the Rockauto.
Well, I got 8 - 2 has larger font red "8" on the box and 6 has smaller font black "8" on the box. Open the box and red 8 lettered has skinnier but longer electrode and black 8 marked box contains shorter but wider elctrode - must have been a production change.
Would you run 2 diffrent types simultaneously?
Longer and skinnier
Shorter but stubbier