8 New NGK Iridium IX Spark Plugs TR7IX # 3690 by NGK

Really good plugs. Installed these on my gt500

Great sparks plugs, i sue these on my Supercharged Mustang, got them here at Amazon for an even way better price compared to the average parts store.

Really good spark plugs, i use them in my cts-v gen2.

After receiving. I compared with plugs from autoparts. No signs of counterfit. No issues with installing and motor runs well

So here's the deal. I run 12.5lbs of boost on a 6.2 LSA in an airboat application (stock LSA boost is 9lbs). I thought after I increased the boost that I needed to go to a colder heat range than stock. After all that's everything I've heard and read online. I installed these plugs and the boat ran rough. I thought I had some ECM re-learning going on and it actually got better but still stumbled at certain rpm ranges. I called NGK. They told me that the rule of thumb is a heat range per 10lbs of boost. NGK heat ranges are 200 degree increments. I pulled these plugs, they were fouled badly after 3 hours run time, put TR6's in and she's a champ again. Bottom line: if you are running a stock LSA or a mild modified one such as me, stick to the "6" heat range. After all this I also found some good supporting documentation online from Lingenfelter and dyno testing they've done with their mod kits. They recommend a "6" heat range as well if you are under 13lbs of boost on the GM 6.2 LSA. I hope this info helps someone.

Consistsnt gap

Boosted car on race gas. Normally swap plugs every year after developing an idle miss. Started running these and they still run good after two years.

Ordered 8, received 4