Need harness help please

ok so I am working on my wiring harness now. It's a 70 dart and I am adding fitech fuel injection and msd dist with 6al. I want to take the factory harness and remove anything I don't need and then add the new wiring making one factory looking harness. My question is what items can I eliminate. I Would still use the voltage regulator correct? Starter relay would stay. Also I don't remember if the headlight harness was ran on driver or pass side.
Thanks for any input
Joe