Ballast Resistor vs. Resistor Wire - 67 250

[67farmtruck]

What is the difference between a ballast resistor (ceramic block with two posts) and a resistor wire, and how do I know which I need? I read a bunch of threads and couldn't figure it out.

I do not see a ballast resistor on my firewall but I do have a cluster of wires emerging from a square black box right next to the choke cable.

I changed out the points, condensor, cap, rotor, and plugs, but no spark. Auto parts guy suggested replacing the resistor first and then the coil, but I don't seem to have a resistor. Could the resistor wire be bad, if in fact that's what I have?

Any advice appreciated!