Sorry for the simple questions. But just want does the ballast resistor do?

it's a resistor that reduces the voltage to the coil to a point where the ign system still has enough energy to fire the plugs & not burn up the coil in daily driving but when starting the ballast is bypasssed which termporarily overloads the coil for a hotter spark for easier starting when the key is in "crank" position for several seconds or so.

RapidRobert if I have a MSD ready to run distributor and I remove the ballast resistor completely as the instructions say, does it impact any other electrical items like the alternator or voltage regulator? Or does the ballst resistor only reduce the voltage for the coil?

Doesn't impact the voltage reg or the alt, only reduces voltage to the coil so if MSD's instructions say to run straight 12V to their coil that is correct.

does that me I can remove the ballast resistor completely????

yes, toss it & connect the sides together which lets you use the original coil positive lead for the switched 12V to the coil/dist.

thanks