Hello! I am going to hotwire my Lincoln cont 1970 car.Battrey to coil.?

I was told that I had to put a reistor between the battrey and the coil so I will not burn out my coil.It is now 12 volts what is the reistor that I need to bring it down to?How many voits do I bring it down to?The last Question is,are you having a good day?Thank you