Old wire is just that old wire. If all the connectors are good and clean, that is half the battle. Most harnesses have a few toasted wires that need repair. If they are not too bad, they can be fixed. I have repaired many. If the bulkhead and fuse blocks are perfect, then you should be ok with a repair job of the melted wires and really clean the terminal ends. If you are not comfortable with that job, then order the new YO and check to make sure all the wires are correct. I check the wire form continuity and make sure they are in the correct places. I checked my buds new superbird harness and it had a wire in the wrong spot. The wipers would not have worked. The only think I do not like about the 70 B body harness is that they only make one for the 70 Charger with the electric headlight motors. The bird did not use that part of the harness so I removed it and change a wire or two to match the original. If your are buying one for your 70 R/T, It will be the same way.