Ok so I'm confused I have a 53 chevy truck it has been converted to 12 v so I have a ballast resistor on it and it is putting out 5.58 volts should I get a 6v coil instead of the 12 v coil I have on it now . I'm using the original distributer .. Is there a ballast resitor that I need to use if I'm using a 12 v coil ?