Some coils have a ballast resistor already attached to them...like the one below. If yours looks like that you won't need the resistor.
Attachments
coil with ballast1.JPG (41.59 KB, 99 downloads)
coil with ballast.JPG (32.99 KB, 99 downloads)


~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end