Yep sounds like a bad wire. Do you have an old set laying around? Just swap the bad one out with one from another set and see what happens. Hopefully it will be gone, but if not then you'll have to check the dizzy. I'll try to explain it better if you end up needing to go that route.
210 isnt overheating for an sbc. What carb do you have? Edelbrocks have been known to cause the fuel to get too hot and spill into the intake. This usually happens when you have a low rise intake and the carb mounted directly to it. Basically it floods the engine out at idle. Can also happen right after shutting it off, makimg it a pain to start.
Another thing to look at is that your advance may be getting stuck, which would cause your hard start you exoerienced. Basically your timimg is too far advanced and is working against the starter.