They run inside the subframe rails from the tank yo the fuel pump. There should be clips underneath the car for the line to be secured with. Most lines you buy are prebent, so they will fall right into place.
Unless it was an aftermarket fulie unit the 67 Pony car didn't have FI. They where naturally aspirated. If so you can route the fuel & return line anywhere you want to. Just keep them away from your pipes or anything that will rub a hole in them.