...more on electrical...
Check the integrity of your wires. Are you running copper core, no resistor wires? If not, the possibility is that you have a breakdown in one or more of the wires.
Also, check the cleanliness of the wires. A layer or coating of dirt, grime, etc. on the outer surface of the wires can cause ignition breakdown particularly at higher RPM.
(yeah, I've had both of these issues over the years with one or more cars...)