Ignore the original cable routing, unless you're building a 100-point show truck. Run a long ground cable from the negative post of the battery to a bolt at the bellhousing near the starter, or to one of the starter attaching bolts. Make sure the cable is at least a #0 diameter. Bigger is always better. If you can acquire welding cable instead of battery cable, so much the better. Hundreds of strands of very fine wire like a welding cable will carry current much better than the relatively coarse stranded cable normally used for batteries. Run the same size cable from the positive battery post to the switch on top of the starter.
For grounding accessories such as headlights, tail lights, and other frame or body mounted electrical parts, run a #4 or #6 wire from the frame to the engine. Connect another one from the frame to the cab, and maybe one from the frame to the bed would also be a good idea. It's just about impossible to have too many grounds!
Jerry
