Best way to run wiring from Eng to Dash

What is the above?

Thanks

Run it through the hole for the fuel line, going through the rear firewall, under the back seat. Then under the carpet on the driver's side, up through the front firewall into the trunk. There should already be some sort of hole or opening through there for wires and such.

If not, just drill a small hole under the carpet on the firewall, run the wire, then glue the carpet back down.

I ran wires for my head temp gauge and just ran a stiff wire through the styrofoam that sticks out right next to the engine wire harness. It comes out behind the side panel. Just pull out the side panel then run the wires out where the engine harness comes out by the regulator and up to the dash along side the body harness wires.
Clark

Thanks to those that replied. It was a snap!