You may want to investigate the dash harness as well. I had a similar case with a 70 B body car I purchased that the engine harness burned up on and was replaced. Car ran fine, though while I was under dash working on some other issues noticed same wire damage. I had to unwrap a significant portion finding much of the ignition wire damaged, including bulkhead connector. Some extreme length of factory wire spot welded to run to other items, contributed to the damage. In the end, I shorted the ignition wire up and double connected to get to the other items. Get some cloth tape for rewrapping harness.