Power wire throught firewall Ford CV P71

I need to pull a wire from the engine compartment to a havis console. Im going from battery, to a 150amp cb in engine compartment then from cb to the console. I dont see anything in the firewall easy accessable. Being that its a police interceptor, the agency who owned it had to have run a power wire but nothing was left. Any ideas? Thanks.

Power wire throught firewall Ford CV P71