Newbie ques: What are Ballast Resistor and Voltage Regulator for?

The car's alternator will put out voltage relevent to RPM to a point, so it needs something to keep it in check and not toast the elecrtical system. The voltage regulator keeps voltage at a level that will keep the battery charged and not cook the rest of the electrical system. The ballast resistor is used because the ignition coil is designed to operate on less than 12 volts. The ballast resistor drops that voltage to whatever the resistance allows. I forget Ohm's law. It's something like for every ohm of resistance, "X" amount of voltage is dropped. I'm sure there are much smarter minds then I here, but that is it in a nutshell. yes, you really need a voltage regulator. The ballast is used for most factory style ignitions that are similar to a Mopar. There are plenty out there though, that are designed to see 12 volts so in their case, the ballast is not used. There are conversions you can do to the Mopar that do not use a ballast and some say is more reliable. THe GM HEI unit is one of those conversions.