I know that this advice is a little late, but whenever I removed a head to replace a head gasket, I would take the head to the machine shop to have them test the head for cracks or warps. The process is called magnaflux crack detection, and it is done by sprinkling powdered iron on the head and applying current to create north-south electrical poles to the head. It isn't very expensive a process and all it takes is a clean head free of oil and grime. Checking for warpage is done by placing the head on a steel plate that is perfectly smooth and true. These are the methods used 50+ years ago, and today they might have a more modern method that I am not aware of.