Wiring harnesses

Hi y'all

I have a 70 Duster originally 318 that now has a 360 motor with electronic ignition. I need a new wiring harness for the motor cause the old one is all hacked and spliced. Was wondering if I order a 73 harness for the motor (since it had factory electronic ignition that year) if it would just plug right into the existing 70 dash harness and just work. Electrical stuff is not my strong point so any info or links would be great. Thanks!