For where you are in the process I'd probably just throw a new set of points in like Jerry said, and run it. Once set the points shouldn't give you any problems, it'll get you by while you're repairing the body, and a little highway driving may just smooth things out a bit. Nothing wrong with swapping to HEI, but you're looking at the dizzy and plug wires (different connectors) and I doubt you'll notice any difference with the stock 283. Money can be spent where you see more value. If it's indeed running fat (main jets rich) that could be a big part of your problem, including maybe some carbon deposits that might affect your compression.