Plug read, opinions needed

TT5.9mag said

Guys, I spent all day on the dyno yesterday. 26 pulls total, lots of carb tuning. Not a mopar so don’t hate me. This is the big block Chevy for my boat, twin turbo, pump gas, low boost, blow through set up. I know how to read a plug, but I’m seeing something I’m not familiar with. On the very tip of the ground strap on 3 plugs I have a color change similar to the timing mark at the base, but at the end. What is the color change an indicator of?
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Not looking at the picture but answering your question the total timing will be the Mark or color change that stops closest to the base ring while the Mark just on the other side of the bend of the tab closest to the electro tip will be the initial timing mark. Typically you will read they want those to be right about even on each side of the bend...everything's unique to the build of course... some people like to see it all the way down to the base Circle , as in ..a lot of total timing but you'll realize or find out how much time it really likes that's my advice and what I know.