Why are my distributor cap terminals burnt?

It runs great, up until 3400 RPM or so. With 22* initial, I’m at about 44-46 total at 3400. So I think I have too much timing and it’s detonating.

The plan was to install the limiting plate to keep me around 36-38, but this damn distributor won’t work. I’ve got the distributor back together now, so I’m going to dial back the initial to see if that helps.
Way too much timing. Start at 34 total.