Use Jerry's idea of bending the copper 90 degrees so it sticks out away from the instrument panel. You could drill holes for your other terminals 1/2 inch apart, which should be enough to bolt them all on to the bus bar.
I hadn't looked closely at a wiring diagram for a 1946 truck. Interesting that it has NO fuses. 47-49 trucks have 5 fuses and 50-54 have only two for taillights and stoplights.
