Grounding the engine

The factory grounding is marginal at best. Another good way is to use one of the unused bolt holes on the rear of the driver side head, run a short no4 starter cable from there to the master cylinder studs. You can buy short starter cables (eye to eye) at parts stores. It matters not whether it's braided or insulated.

The thing is, you want the main ground to the engine block............heavy starter current.

But all the lights heater, cooling fans, electric pump, etc, if used are normally grounded to the body. So you want an improvement over factory as the alternator and the loads get larger.