denso 3381 are one step colder plugs im looking for step 2 colder plugs
what do you mean by eagle engine?
Now that I'm not crawling into bed I'll give a longer answer. Eagle is the designation of the '09+ VVT 5.7L engine, Apache is the 6.4L VVT, etc.
When it comes to making decisions on nitrous systems I will never hesitate to call up the guys at N2Outlet because they regularly race nitrous hemis and have a wealth of first hand knowledge on these engines.
The Denso 3381s have a great heat shedding ability and can be run with up to a 150 shot. I am running them gapped at .028" as my DD plugs on my engine atm and ran them with a 150 shot when I was N/A with no issues. There's variation in how plug heat ranges are measured by each manufacturer so it's not always a 100% comparison especially when you start comparing shrouded/non-shrouded and changing the gap.
I haven't been able to find any plugs that run 2 full steps colder for the VVT 5.7L and have the required seat shape. I ran the Brisk RR14 plugs when I was running a 150-175 shot of nitrous with my D1SC and they're 3 steps colder according to Nitrous Outlet. Nitrous Outlet claims the Brisk ER14S claims to be 2 steps colder on the Eagle 5.7L; the RR14 and ER14S are both HR 14 plugs so you see why there's confusion if you just go by the manufacturer's numbers.
These are the two comparison charts I use when deciding plugs
https://www.densoproducts.com/learning-center/article/225/heat-range-conversion-chart
Spark Plug Cross Reference HEAT RANGE CHART
What's your compression ratio with the stroker kit? If it's 11 or higher then I'd go with the RR14, if it's less than 11 you can run the ER14s but the 3381s will still be good. The benefit of the Brisk plugs is they're a shrouded tip and will dissipate heat better where the 3381s are a projected tip.
