Ok, first off, i spent most of the day using the search function and came up with some useful info on spark plugs.. I have AFR heads so i need a gasketed spark plug. I have a Procharger with 12lbs of boost. The trouble i am having seems to be the spark blowing out at higher RPM's and acting like a rev limiter. I currently have TR6 plugs gapped at .035" but i need to replace these with a gasket type plug. Should i get a non-projected tip or projected tip? What should i close the gap to?

 

Not sure if this will help, I'm using a Champion C57YC, stock#791, gap .028 to .030 max. With 1st gen Dart Pro1 heads, @16 lbs boost.
The C57YC is a pretty cold, 3/4" reach, gasketed plug. I'm not sure if it is projected tip??
It's the plug a dyno guy told me to run. Works well in my deal.
---Bill.

 

You'll want to run a non-projected tip plug. I ran projected tips at first but ran into the same problem. Going to a non-projected took care of it. You should be good with 2 heat ranges colder then stock. I tried 3 ranges colder using the Autolite racing plugs which are non-projected with a cut back ground strap, but they were starting to foul during cruise driving.

Ken

 

-7 NGK non-projected tip gapped around .030" sounds good to anyone? Definately start by closing the gap, it can do wonders. Stronger spark would be the next step after that. I was running FR5's projected tip and they are great on motor and cruise but a 150 shot made them look a littrle too hot so I went to the non projected -7's. These look great and should be good for more juice too. Yes both of these are 3/4" gasketed for your style head.

 

I am using an Autolite 3922 plug in my AFR 180 heads with my D1SC at 14.5#'s of boost with a .028 gap, it seems to be the perfect combo for my car.

Last year when I initially had my car tuned I was running a bigger gap and above 6300 RPM's I was seeing similar effects of the boost blowing out the spark.

I reccomend staying away from NGK plugs as my tuner as well as other tuners and other members on here have had issues with running them on their FI applications.