Thats a bummer!
I would think about why it locked up. Leaky injector? Overheated? No oil pressure? Even a tired old junkyard engine should have lasted for a few months, just smoked and used oil.
It has cathedral heads, which means the engine could be 20+ years old. It might have been a good idea to have peaked at the crankshaft bearings, and pull the heads for inspection. If the cylinders looked good, throw in new bearings, rings and run it, without bringing it to machine shop. Machine shop is now in its future with the seized crank.