I was just inspecting something else in the engine and happened to notice a large braided copper ground wire was completely severed in half. I don't know what it grounds, but its rather large, and come from down towards the block, the ground is screwed off with several other wires right near the coil-pack on the driver's side fender. Any idea what this is a ground for, and can I splice something like this (if so, what gauge wire should I use?)?

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87 300E
202k on the clock