7`s are hotter than 8`s in NGK`s............didn`t notice if you had a wideband or not but tuning idle, cruise and wfo can be a bear w/out one............doable yes but a bear otherwise especially if you have an off idle stumble and don`t know if it`s rich or lean.
I went the wrong WAY I put in 9's instead of 7's
HEMI-ITIS has no cure. My condition is fully BLOWN!!
I went the wrong WAY 
I put in 9's instead of 7's 
