Spark plug reading
The ngk 4 is a hot plug. Looking at your pics it appears to be holding too much chamber temp. I like your previous plug choice better. The 6 or maybe even a 7 would be better. And you need a degree or two more total timing IMO for best power. If you’re confident in the tune up, go make a few hard acceleration runs. Then leak it down and read the plugs, that includes cutting one open.