If you have a coil rated for 6 volts in a 12 volt system, it won't work. The ballast resistor is bypassed during starting, delivering the full 12V to the coil.SpeedDemon383 said:
If it fires up, then as soon as you release the key it dies, your ballast resistor is bad.
All internal combustion engines have coils. Your car should take a universal coil, which is the same on every vehicle from the fifties straight on up into the nineties (with a few notable exceptions).