86 Shelby Charger
Low mile 8v T2 engine out of 89 Masi TC
87 GLHS Stage 2 LM, 87 wiring
Currently no intercooler hooked up, wastegate hooked up to manifold, 5 psi boost max at WOT

Plugs are RN12YC Champions, new
Denso plug wires, new
Airtex/Wells cap/rotor, new
Stock OEM 31 year old coil

Under light throttle, there is no misfire at all. Under part/heavy throttle the car misses and breaks up badly. Sometimes it is worse than other times. Sometimes it will start accelerating well, then like flipping a switch, you can feel a loss of power and misfire. Or, it will start missing badly, then clear up and accelerate. Engine temperature seems to not change the symptoms.

Fuel pressure KOEO is about 50 psi. KOER about 53 psi at idle, 57 psi with vacuum line off regulator. Fuel pressure while driving remains steady, and under WOT up a hill will hit about 60 psi. This is using a snap on gauge ran up and out of the hood into the car.

I changed the plug gap from 35 thou to 25 thou and took it around my neighborhood. It seemed to help. The misfire seems to be more inconsistent, and before where it felt like multiple cylinders were cutting out, now it feels like only one cylinder is cutting in/out.

Any thoughts or tests I should perform before ordering a new coil?
Also, this setup was running GREAT for about 50 miles after I got it running. Then this started happening.