Just as important as the main battery cables is the engine ground cable. Because the engine sits on rubber isolators, it does not inherently have good grounding capabilities for sending units, ignition, charging system, and more. A simple ground strap from the back of the engine to the firewall is what Ford has used for decades and it works well. Again, a concours-type ground strap like this one from NPD means it will be the right length with the proper eyelets for your application. Don’t forget it, especially those doing engine swaps, as it’s easy to leave it on the old engine.