Burned bulk head connection

I’m not sure why 65 (and 63) harnesses both had the wires from the battery and ammeter connected to heavy duty buss bars at the junction box. Then inside followed the customary branching off with the black wire. It could certainly cause problems at the spice but not at the junction box. On my 65 I am running through maxi fuses a modified harness the 2 wires to the ignition switch and one direct to the headlight switch as Mopar did in the 80’s