Without bad luck, I would have no luck at all!

Yesterday the engine  back in my Carat. Today the engine was run and it was
beautiful. Sounded so good. While idling to allow to warm up and begin the
break-in, it stopped suddenly, never to start again. In fact, never even to
be turned by hand with a wrench  - seized solid. The rebuilder is
flabbergasyed. I'm flabbergasted. He said in all his years on rebuilding VW
engines 'he never had  a Vanagon engine do that. Two aircooled ones but
never a 2.1 L WBX. Anyhow,  come Monday, out it comes for a tear down
again.  I've a choice: take one of his other rebuilts, or wait for this
one. What would you do? There are six to chose from. Jim is an excellent
mechanic, and I think this is a fluke!

And, anyone want to speculate on the cause of this one locking up?

John