Yes always to new and updated and extra grounds. Ford was a little weak in the grounding department when it came to Broncos. Every other vehicle got more love, but not the Bronco in this instance.
You need the main ground cable to the engine block of course. Then you need a dedicated body ground from the battery to somewhere nearby. Then another one from the back of the engine to the firewall (Ford never did this for Broncos, but did for other vehicles) to help with the rest of the stuff.
Those are the bare minimums. Often, depending upon how much rust, how many layers of paint, or just old age, you need a new dedicated ground wire from either the battery or just another part of the body that is grounded, to the radiator core support so that the headlights and turn signals get a better ground than they usually have.
When these were new, all the spot welds and contact points between body panels was enough. Fast forward 50 years and those interfaces are not so good at passing electrons anymore.
So as we like to say, grounds, grounds, grounds... If you can think of or see another good place to put another jumper wire (think windshield frame, or dash board) it's usually a good idea.
Good luck.
Paul
