Wiring diagram help

You'll find the majority of the wire colors never changed. Their routing changed quite a bit. A 67 model had the reverse lamp switch inside the cabin.
Your 71 has that switch mounted on the trans. The wiring would go through the far right member of the bulkhead connector.
Your 67 diagram would show no wires in that connector other than those to the wiper motor. Your 71 will have 2 or 3 additional wires in that connector.
Wrong diagrams can cause major headache or worse.