Appreciate some input on spark plug reading

Demonx2 said

I should have listed the heads right up front - my bad. They are simple Eddie RPM with somewhat mild bowl porting. So I believe these to be the limiting factor for my combo.
It's not that I'm not happy with it. But like everyone, I want to get all there is out of what I've got!

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If I had to guess, the limiting factor is the heads. Even fully ported, they are small on a 4 inch motor. I have had many a 4 inch motor wheeze the last couple hundred feet with such heads.
To me, the cam is a good 10 degrees too small as well. My cam in my stroker is 260@50, and I know it’s a big limiting factor.
I swapped it out of my previous stock stroke 360 and used it in this new motor merely because I had it..lol
It ran 11.22 at almost 119 at 3360 at 10 to 1 in that 360. Maybe a touch big, but definately a good bit small now. Excellerator, 950, 1 5/8 Doug’s headers.