need advice for break in plugs on a 4.6 dohc forged everything and ported everthing should be around 400 hp on 93 oct. i dont know what temp range to go with or even which brand, do i need something different for break-in only?
thanks
-chris

 

I assume you are FI. So you want to go one heat range cooler than stock. NGK TR6's are a great choice. Cheap too. -Mark