James, what computer are you going to use and is it manual or auto.? I used a Gregory's E.F.I manual I think its volume 4, has very easy to follow wiring diagrams for Holden V8s and step by step test instructions for all the circuits including voltage range, fault codes and drive motors ect. Studding the ECM wiring circuits and system operation diagrams it quickly makes sense. If your going to use the original harness and computer there is only around four wires you need to connect to get them to run. I know when you look at the harness it looks very daunting, but its not that difficult with only a basic understanding of wiring and electrical relays. Some auto electricians charge $500-600 just to do very simple joining of a few wires and put a fuse and relay into the circuit. And when you complete the wiring it will give you the confidence to maintain it well after the rebuild of the car is complete. Its a learning curve well worth taking in my opinion.