I just want more current flow for when I put a bigger sub in.
Plus the wire from the fuse box to the positive terminal keeps coming out and needs to be replaced.
I'm not sure how to get out the wire from the fuse box.Is there a way I can upgrade it to 0 gauge?
Negative to Chassis: Upgrade. This is return path for some circuits.
Negative to Engine block: Upgrade. This is return path for some circuits
Positive to starter: No need not upgrade. This only supplies the starter. If you're having starter problem, it's something else, not the wire size. Just make sure you have good connection.
Positive to fuse box: Do not upgrade. Fusible link designed to protect stock wiring is integrated in that. If you need to power additional equipment use separate line with fuse to the battery. If battery can handle cranking amps or a winch to move vehicle weight, it will handle your audio amplifier.
the wiring running to fuses is plenty for what the fuses need if it needed to be bigger they would have come that way from the factory if adding anything big that would cause a problem that should be on its own line from the battery not the fuse box.
You can also upgrade alt to pos terminal.
Concur.
If upgrading alt to batt wire, just eliminate the block that looks like a ferrite core noise suppressor.
It is NOT a noise suppressor, but a junction point.
I am not aware of anyone who has ever used that junction point in the past 27 years. That's just waiting to loosen/corrode (like an appendix with no real use, just waiting to get infected). Get rid of it and replace stock alt-batt wire with one-piece thicker wire direct from alt to where it joins the fuse block.
Don't bother with the wire feeding the fuse box. Just upgrade the battery to body, engine to body, and alternator to battery wires. Leave the stock wires in place, and add the other lines ontop of them.... 0ga for the engine / body grounds.
Concur
Make sure you fuse the alternator wire. 4ga. is fine for that wire.
I do not think it's necessary to fuse alt-batt wire. Stock is not fused. Changing it with thicker wire actually makes it safer and able to handle higher current than stock.
I read all these things about "alternator to battery" but my wire goes from my starter to my battery...
You should also have a thinner wire from batt pos to fuse block. Fusible link is integrated in it. This is how Fusible Link wire looks when disconnected from fuse block.