Plug wires arcing

My '97 Cav has had a rough idle for some time now. Tonight, I raised the hood while idling and noticed the plug wires were arcing across to the head. It gets worse when accelerating. The wires and plugs are about 2 months old. Belden wires (NAPA). I put anti-seize on the plug threads when installing the plugs. I have done this for the last 30 years and never had a problem. Has anyone ever heard this to be the cause of grounding?
Thanks

Sounds like you got bad wires or a plug(s) is cracked causing the spark to jump. I had that happen years ago, but it was just one wire. In the dark you could see the spark jumping (and hear misfire). I always use anti-seize too, no problems ever.