The 6AL box with a MSD Blaster coil puts out a mega spark! It will fire spark plugs with the ground electrodes burnt completely off the plugs without even missing a beat. But, if the spark plug wires, or the cap and rotor are not in great condition this large spark will find the path of least resistance. Look inside the cap for carbon tracking.

Make sure you don't have the 3000 RPM test chip installed.