MSD-5C

From that info(Holley) that was posted above

Ballast Resistors: If the vehicle has a ballast resistor or resistor wiring leading to the coil, leave it inline and connect the Red wire of the ignition before the resistor. If there are no resistors originally, the Blaster Ignition and MSD 5 do not require it. For aftermarket coils, use the coil manufacturer’s recommendations.