Spark plugs

[jcw31]

Billy how much do you attribute the difference to them possibly being a different heat range than an iridium plug? A friend had a zz502 crate when we changed from rapidfire [a multiple heat range]
to ngk copper the car also slowed down. The interchanges between different companys dont always match correctly.Also the rapidfires while I agree is a very good plug also has a v tipped ground strap which helps.

Joe

[Ed Wright]

I had a box sitting on the work bench in my dyno bay, nearly full of new or nearly new NGK spark plugs we had to pull out of customers cars to stop WOT misfires. They always said "I never heard it miss like that!" I would tell them they never stood near the tail pipes, while it was running wide open, in a tin building before. And that it needed fixed before I could tune it. Not all NGKs that came through there had a misfire problem, but I don't remember having to replace another brand of new plugs like that. About filled that box up before we shut the shop down.