These plugs were in my 03 when I got it. It was a little sluggish and did not like having a lot of demand put on it. I changed out to OEM plugs and the difference was night and day. I did a lot of research on plugs and there are a lot of claims made. I talked to alot of people who know these trucks better than I do and the majority rule was the OEM plug was the best for the hemi.