relocating battery

Yes that is the shut off. It is a pull switch that comes through the reverse light. The light still works.

The two cables coming through the heat shield are , One is the large cable to the trunk the other is the original battery cable to the starter

The smaller red wire goes to the relay.

The other two black wires are One going to the alternator you see in the pic. it is a one wire 100amp GM race. My charging system is a 8 inch wire. The other black going front goes to the fan relays.

There is no harness on my motor.

I ran a power wire from the trunk switch , Into my car that powers the fuel pump and the Ignition system . It runs to the switch console in the car.

I tried to keep as much of the factory car intact.