i need to know which spark plug is the number 1 spark plug on my twin turboed 1990 300zx

 

NGK pfr6b-11b

 

its a good thing that means a lot!

 

According to SpecialtyZ, NGK Iridium IX

NGK Iridium IX Spark Plugs - Heat Range "7"

 

^^^ According to any "store" the more expensive parts are always needed.

It's been proven time and time again that Iridium & Platinum plugs don't "increase" power, but they do last longer. All those people who swear they "get 33% better mileage AND 33% more power" are experiencing what's called the naive placebo effect.

 

Maybe two of their spark plugs were busted before trying out the Iridiums

 

Go with platinum. I went with bosch iridium plugs and was missing on 1 and 2. Switched them to NGK platinums and guess what. I was firing on all six