Quote Originally Posted by Liquifire View Post
Just a question.......Does NGK make a spark plug equivalent to our stock ones that is the same heat? Does anyone know the number for them? Thanks
Actually, yes they do. The TR55 (copper), TR55GP (platinum), and TR55IX (iridium) are all in the same heat range as the stock plugs.

But yes - I would run a 1 step colder plug at a minimum - even on a stock GTP.

Edit: And, little brother - the Autolite 606's are the direct stock replacements.

-Swash