64 barracuda fusible link
Jim the G slot is the hot wire coming from the starter relay. It doesn’t make sense to me why they would have a solid hot wire and a fusible link also.?
The fusible link is undersized section of a specific length to create a fuse that can tolerate short periods of higher current.
If the whole run was undersize, it would create excessive resistance during typical use.
I dont have a '64 FSM but typically the main wire is 12 gage and the fusible link is 16 gage.
If the battery is a little low when recharging begins, the battery may draw 20 or 30 amps for a minute. The 16 gage wire won't have a lot resistance to that, and will only heat up slowly. As the battery recharges it draws less and less current. So within a minute or two the current is down to 10 amps and the 16 gage can easily carry that with minimal resistance.
On the reverse situation, alternator dead, its possible to drive for hours on battery alone. Even with the headlights on, the fusible link will only cause minimal resistance. It's not ideal - it may get a little warm - but not going too many hours at night on battery alone anyway. LOL been there...
One situation where the power circuit can get pushed to where it gets damaged without immediately failing is recharging a nearly dead battery with the alternator.
