my new wiring harness says to mount to a flat surface but the wiring sticking out the back would prevent mounting flat, without pinching wires, how would I get around that?, thanks in advance
Visualize a cardboard box with two opposite sides cut off and the two remaining top flaps folded outward. Build one out of tin with the height of the sides appropriate for your needs. Weld nuts on the inside of the "box" so that you can bolt your fuse panel to it then weld or bolt the "Box" to the inside of your firewall. you can cut a hole or relieve the "box" as needed to allow the wires plenty of room to exit the fuse panel .