Help! Newly renovated engine got stuck while cranking it...

Yes, I could spin it around by hand like normal. And when we tried the start motor first it sounded and felt like normal, with the only exception that it wouldn't ignite. It was first after we changed the distributor we really started to notice anything strange. And of course this was also after we had flooded it and blown out the cyl with compressed air. After that we only bursted a few times with the start engine, between the battery changes, before it got to a state almost completely stuck...

The ignition timing might not be completely correctly, but since we can't even turn it by hand I am positive that isn't the problem... I think the mechanic that helped us has a borescope, will check that with him next time I get a chance.