Elvis, To give you a little facts about the coils and what I have measured. #1. MSD Coil derived by .7 ohm resistance and the coil primary is wound to hold the current with out any further resistance. Thus 45,000 volts. Also derived by windings on the primary as you know. #2. Pertronix coil. 1.5 ohm coil. 40,000 volt. Add the extra 1.5 ohm on the car and you will have a conservative average 30,000 volts. But, it is designed to run with the internal resistance only. #3. Bosch coil's all are 1.7 ohm and they want you to use an extra 1.8 ohm to give the conservative 25,000 volts with loner life. Total 3.5 ohms. John Hervey www.specialTauto.com [Very, very long quote snipped by moderator]