I did a similar re-wiring job on my '71 when I had it torn down. I used the EZ wiring harness, and it is fairly easy to do. Mine was a complete aftermarket re-wire though. All aftermarket gauges, a/c, stereo, cooling fans, etc. I re-used very little of the factory components. Just things like the ignition switch, wiper motor, headlights and tail lights. If I were to do another one, I'd still use the the EZ harness again, it just might require a bit more head scratching when more factory components are used.