Misfiring as I crank the boost, best way to check plug wires?

Car seems to be blowing out spark above 22 psi of boost. I did a bunch of re-grounding which really helped my charging system...

However, I am now wondering if my cheapo MSD plug wires have chafed through or something. Any good way to check for spark blowing through the side of the wires short of spraying everything with water in the dark? This is pretty frustrating, I have been coil on plug for years and plugwires haven't been an issue til' now.

Thanks guys.

Spraying water would work. Also what kinda of plugs are you using and what are they gapped to?

I don't recall what the plugs were, but they are new. They are gapped pretty tight (.28 or so) I am using LS1 coils FWIW. The plugs have been in my toolbox since last year, they may be a heat range colder than stock. I can't remember.

I have had this problem since I exceeded 20psi. Certainly no misfiring at 14 psi or so, or at idle. This thing would burn RICH afr's easily about 6 months ago.. like in the 9s.

Arcing through the boot on cylinder 6... awesome. Found it by spraying water and using a test light around the plug boots.