I have been looking for either a 235 or a 216 head for a while now and considered just getting another engine as an option as well. Problem is just because an engine runs, doesn't mean the head or block isn't cracked. They will run just fine, sometimes with a blown head gasket or other serious problem.
The only way is to make a deal to have it checked and only pay for a good component. Otherwise it is just an exercise in buying scrap.
