Critique This Spark Plug

This plug came directly from a low deck 498” engine with dyno time only. Had 7 pulls on it and would like your expertise on anything you can surmise. 13:1 comp., sunoco Blue fuel 112 octane, pretty even egt across using a Wilson moded Intake. Pulls to 7900. Thx

I think Steve Morris would say it is a little rich:

https://www.youtube.com/watch?v=MecCoercp-s

What does the ground strap look like?
Does that fuel normally look yellow on the porclyn?

340….thanks for that link. Very informative. He is a Force for sure!



Cab….not sure on that fuel looking yellow, but all 8 plugs looked the same.
Here is the strap before dismantling:

Learn something new all the time. Never knew you could separate the plug like that. Do you just twist them apart with some pliers?

You either get a tool or cut them apart on a lath. May be other ways, don't know.

https://nitrousoutlet.com/i-30560870-spark-plug-cutting-tool.html

It may be a little rich if you are digging for maximum power, but I would say it is just right if it came out of one of my engines, I like a little rich just to be safe, plus you don't need to be changing jets if it happens to be a cool day at the track.

That looks a little rich to me
How much timing and what heat range is that plug?

That’s what i was thinking, but wanted more experienced opinions. Thx. I do like the idea of it being just on the rich/safe side.

Timing at 35 with a -1 Indy head chamber. Ngk R5672A-8 plug on recommendation.

5/8" hole saw without the drill bit cuts them easily.
Doug

I would try a #7 plug next

available at most hardware stores, and no more than about $15, even if you have to buy the mandrel.