Sounds like it was preigniting or running very lean and melted the piston top. That piston will have to be replaced, depending on what kit it is you may have to replace the whole set. Made in usa on the cam means it is a performance cam of some sort, you will need to look for numbers stamped on it to determine what you have. Normally cam markings are on the end of the camshaft, sometimes they are under the washer end but most of the time they are on the opposite end. Some times it can be on the shaft itself. You will need to determine what you are going to do as far as rebuild before you get to deep into powder coating, it is more durable but requires more prep work, I find good engine paint last a very long time if you clean the surfaces well, costs less and is easy to do it yourself at home with no special tools.