IT is a common myth that the resistor has to be removed with msd.

If you wire the MSD as per the instructions, it specifies that a ballast is not used with msd. true. BUT it also specifies that the old coil + wire can be used as the switch on wire for the msd unit, AND that the reduced voltage on that wire,will turn on msd.(the msd is supposed to be wired directly to the battery for its main power feed, not the old coil + wire. The old coil wire is now used as an on signal)

What is meant by the statement that there is no ballast used with msd, is that there is no ballast resistor in the coil positive wire between the msd unit and the coil, not that the one on the car has to be removed.

The last MSD I installed even specified, that it may be necessary to install a ballast in the on trigger wire, because even a small amount of voltage on that wire( a couple of volts), will keep the msd on, and may cause a situation where turning off the ignition switch won't shut the car off.


It'll work either way, and many run without the factory resistor, and many run with it, but if a change in running is experienced with the ballast removed, there was something else wrong prior to removing it.