when it rains it pours

update, well i got my new front lights/engine harness. i also went ahead an got a new coil, ballast, ecm, voltage regulator, and altenator, and proceeded to tear into it. my biggest worry was answered when i looked up under the dash. the dash wiring is fubar'ed aswell. theres a dark blue wire under there that connects to the ignition switch and also heads over to the fuse block its completly burnt up aswell. my nieghbor across the street has a 71 4dr dart that he said i can have the harness from. my main concern is will i be able to use it? my dart is a swinger340 and has the rallye dash. can i take the connections off of my old harness and put them on the regular harness? i hope this can work cause i cannot afford a new dash harness, let alone get another used one my well has run dry