Cylinder head temps and spark plugs, can it make a 20-40 degree head temp difference Options

[DRPHIL914]

so sunday afternoon i decided to take a look at my plugs, last changed out 3 years ago, and wanted to see how they look, check gaps etc, while out i just changed them out for the Bosch super than i had on the shelf since i got them at okteenerfest a few years back,

now, i watch my CHT gauge and temps really close and ive been driving the car more past few weeks with the good weather and ive been sorting out a lot of issues, but watching my temps at certain speeds and RPM levels.

So yesterday and today i noticed that where cruising on the flat at 60mph ive been right at 280 or so but not over 300, and yesterday and today i was at 320-340. and passing pushed up to 350, and i had not touched 320 in the past 2 weeks driving the car regular.

so, ambient temps are not up that much it was 60-65 past 2 days. my question is , could the plug change make that much of a difference ? or did something happen with the thermocouple around the #3 plug that is making it read higher? thats 30-50 degrees higher than where i was at just days ago.

I did some more plug research and i know tha the Capt. and others recommend the
Bosch W7CCor W7DTC
or NGK BP6es, or theBR6es/ B6es , the difference being r for resistor, p protected.

so with this , what do you guys run on a 2.0 or any for that matter,
can the change in plug make that much of a difference?
- I will look at the plug box closer, but outside of the box just says Bosch super

- also plugs looked pretty good no black soot build up, actually looked like tune is pretty good but maybe just a touch on the lean side, but he AF indicates highway levels being at about 13.5 but vaires from 12.5-14 more on the lower side on idle and lower rpm crusing around town and more lean on higher speeds , it does drop quite a bit to 12. 5 on WOT.

Phil