On the racing Shelby we mounted it on the firewall, inside the car where the heater used to be....obviously not possible in a street car. I built a restomod
64 1/2 convertible and mounted it between the hood hinge and heater motor on the firewall. I folded a piece of aluminum, attached it to the lip where the cowl and firewall join. The box was mounted with 4 bolts, rubber washers and lock nuts. The wiring harness ran behind the plate, making a natural holder. Looked trick, stayed dry, functioned flawlessly and minimal wiring work was required.