68 Barracuda Alternator upgrade.

All these circuits run through their own individual spades in the bulkhead with the exception of the power feed in, which is now split between 2 wires going in, that do not have the alternator power feeding through as well.

If you do a headlight relay mod that lessens the draw thru the bulkhead further because the brunt of the power feed to the headlights is from the battery right to the relay in the fender and out to the lights. We know the primary point of the relay mod is brighter headlighrs, however The secondary point of the headlight relay is to save the wiring, bulkhead , and switches since with the relays installed it now takes only maybe 1/10th of 1 amp to trip them with the headlight and high beam switch.

Now the factory determined that draw with the factory accessories and Lighting along with a 20A max output alternator to be sufficient for that size bulkhead connector and wire. You have removed the alternator from the equation with a bypass and now have two feeds coming from the battery and going through the bulkhead instead of one so now your amp draw is cut in half through two wires. By this logic if you twisted the two wires together which are 12 gauge you would essentially be pumping the power through a 6-gauge wire at the bulkhead we are keeping them separate because it's easier that way to wire it but you are splitting the amperage between two 12 gauge wires

Now a heavy duty stereo with an amp, you would be running a dedicated amp feed from the battery anyways thru the bulkhead with a rubber grommet.