Here is another bunch of conflicting verbage from Vintage Performance.com about the "Standard Pertronix"...(older version) FWIW
"The standard Ignitor is recommended for basically stock or mildly modified engines. Teamed up with a PerTronix 40,000 V Flame-Thrower Coil, the Ignitor will provide more than enough spark energy for almost all applications. We have customers running in the 11s and 12s in the quarter mile with this combination. The Ignitor can be used with OEM type coils.
Caution - some aftermarket coils have lower primary resistance than an OEM or the PerTronix Coil. Using one of these could damage the Ignitor. Rule of thumb - for 8 cylinder applications the primary resistance in the coil circuit must be 1.5 ohms minimum. For normal performance 6 cylinder and 4 cylinder applications the primary resistance should be 3 ohms minimum. Primary resistance is measured across the negative and positive terminals of the coil with all other wires removed. If you have a ballast resistor in series with the coil, its resistance is added to the coil resistance.
Many older vehicles have resistor wires feeding power to the coil when the engine is running. The resistor wires are bypassed when the engine is being started and full battery voltage is fed to the coil to facilitate start-up. These wires were intended to reduce the voltage to the coil once the engine was running in order to extend the life of points. Most of the time an Ignitor will work well with the resistor wire left in the circuit. However, in some cases the resistor wire, or its connections, may have deteriorated over time resulting in an excessive voltage drop at the coil. This could adversely affect Ignitor performance, especially at higher RPM, resulting in misfires. The resistor wire may be bypassed and a full 12 volts can be fed to the coil as long as the coil resistance requirements mentioned above are met."
Many people are having very good luck with Pertronix. Some of us engineers and enthusiasts have it in our heads that the resistor protects the points. So no points, no resistor needed. BUT Pertronix circuitry needs a certain resistance to remain dependable. With or without a ballast resistor, the ohmage math must result in what a version needs.
Also: Notice my RED in above "info".
