here is a 64 diagram
green(right) and yellow(left) are rear turn/brake wires
dark blue(right) and light blue(left) are front turn
white goes to the stop lamp switch
brown goes to the horn
purple goes to the turn flasher
maybe that is close to your '63 wiring?
i have a pdf file for my '80 (should be the same as a '78)
green(right) and yellow(left) are rear turn/brake wires
blue(right) and light blue(left) are front turn
white goes to the stop lamp switch
purple goes to the turn flasher
brown is hazard flasher(you won't need)
black is horn
1980 wrg diag 01.pdf
1980 wrg diag 02.pdf