I bought this car with a blown head gasket and I'm not sure how long the people drove it after it overheated. What do you think the chances are of a cracked head or a cracked block. It does still run and I don't see any water leaking out of the engine anywhere.

That's good that there's no coolant leaks
what's the oil look like?

The oil is pretty milky and it's steaming out of the exhaust. Also it's bubbling and whistling up into the coolant reservoir. I took the thermostat out and tested it with boiling water and it didn't open so I believe that was original reason it overheated.

Aluminum blocks don't crack. Since the engine still runs, chances are that the cam races are not warped and a new head gasket is all that is needed.

It will be a crap shoot, but easier than finding a used engine and replacing it.
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Keeping it running is better than buying new

Ok thanks. That's pretty much what I think I've decided to do is just to replace the headgasket and see what happens. I am going to take the head to a machine shop to get it tested and milled if need be.