Spark Plug INFO you should know

kennerz · August 4, 2019

This just an FYI about some plugs I bought from summit. A year or so ago there weren't a lot of options for replacement plugs. (outside of delco) I ordered some Denso plugs as soon as the were available through summit I believe. P/N ITV16TT was prescribed for a 6.2 L86. I noticed when I replaced them the reach was visibly shorter than the delcos ( about 1mm).

(Truck runs good however mileage was down 1~2 mpg after the denso plug change that I chocked up to going to heavier tires and tuning with diablew.)

about 6~8 months go by and NGK comes out with a L86 application. I've always had good luck with NGK so I purchase them and they sit for 3 months until today.

NOtice that these NGK's are about 1mm longer than the Densos. And the gap is visibly larger. Anyhow install the plus and all the sudden mileage goes up 2 mpg , more power, better response, smoother, etc...

Point of this post is to note that some places are recommending the wrong replacement plugs for a L86. The wrong plug will run fine, but night like it should, or does with the correct plug.

The NGK plug is ILTR5E11, or the LT1 version of the trusty TR5 iridium.

THe Densos looked new after 10k, so the improvement was not because the plugs were old. I'm not against Delco at all, just have had exceptional performance from NGK plugs in the past and this time is no different.

Run whatever you like But make sure you get the ones that have the correct reach and proper gap being as coil on plug ignitions can easily fire a larger gap over .035.