What spark plugs are you using in the 340?

[MerlinsMopar]

Been a long time since I got to fire a 340 and bought up some old stock champion n9y plugs as that was my preference years ago. Appears they dont make them anymore. I also used ngk bp6es and dont care for the resistor type. I may also need to go a step colder but not sure till i get to start the serious tuning this spring. I also figure heads and cam set ups change heat range. Mine is .536" lift 108cl with 2.02 heads. What are you guys using these days?

 

[Mattax]

The box number is all many of the parts store people know. So when you ask for RN9YC or RN12YC etc they look at you crosseyed.
There is a small hex version for the 12, not sure about 9.
In any event, lemme see if I have the box number. Its somethig like 404.
9 is relatively cold. A couple years ago when I was putting a bunch of miles on but no racing, I experimented with one step cooler. This is on a lower compression flat top piston 340.

edit 404 is 12.
still looking for 9

 

[Mattax]

415 contains RN9YC spark plugs.