4 Prong Ballast resistor?

[Curiousyellow71]

The brown wire is the same circuit as as the blue, if its brown on one side of the ballast and blue on the other...they changed the color because of the voltage drop after it goes through the resistor. You could put a wire splice and go from blue to brown. But that isn't really necessary just hook the small red msd to the blue and your msd should be ready. Cleaning up the wiring for the alternator may take a bit of work but Imo worth it to get rid of most of the spaghetti. The wire from the alternator the diagram should help you figure it out.
You will get there...

 

[383man]

The Brown wire is the ballast bypass while cranking which is why is called the ign 2 wire. It just bypasses the ballast while the eng is cranking over. Basically for MSD the brown wire (12 volts in crank to coil) and the blue wire (12 volts in run to coil) are hooked together and go to the coil which the factory has done so at the ballast on the .5 to .75 side so if you just jump the ballast wires and then hook the original coil + wire to the red MSD 12 volt run/start wire it should be fine. Ron