Depends on the coil. Some "12 Volt" coils like the one on my old 67 were hooked up to a ballast resistor. And if you look it up at say Autozone, it will tell you it is a 12 Volt coil. It is not but it is in a 12 Volt system. You need to see if it has an internal resistor. If it does, then no external resistor is needed. You can tell from the P/N on the coil if it can be read.
