The E-SparkTM Ignition System is designed to work with most stock ignition coils and aftermarket high performance ignition coils. For optimum performance in systems without a HyFire or similar ignition control, use one of Mallory's 3 specially matched coils eliminates the need for a ballast resistor or a resistance wire. These coils are: 29219- Chrome Canister Coil, 30450 PROMASTER e Coil and 29450 PROMASTER Classic Coil. Spark Plug Wires: