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?
View attachment 1715978328 View attachment 1715978329 View attachment 1715978330 View attachment 1715978331