[Michael C Henry]

Another point is the system with the box gets 12V, and the box supplies the corrected power to the distributer and coil. When operating just the distributor and coil, power usually must be routed through a ballast resister except for starting. GMs use a terminal stud on the starter solenoid and Fords have a terminal on the starter relay (starter resister bypass) power routed to ignition (usually the coil) bypassing the ballast resister while cranking. on systems not using the box, Not using the ballast resister can cause some coils to overheat and be permamently damaged.