Classic/Antique Car Repair: Cracked engine block, machine shop technology, block drain

Question
Hello,
 I have recently looked at a 1964 Chevrolet, stock, 283 rebuilt engine with a crack in the block due to freezing. The seller has the engine running on an engine stand. He states he rebuilt the engine this fall & did not freeze protect it & it froze & popped a freeze plug. The engine now has anti-freeze in it & a new freeze plug installed. After about 5 minutes of running, with a radiator & thermostat, on the stand a "seep" appears on the lower right side of the engine, about 2 inches above the oil pan . The hair line crack is next to the block drain plug & is about 2" long. Is this engine block repairable or should I stay away from this engine????? If repaired, would this be a permanent, confident repair. Has machine shop repairs & technology improved that this crack can be safely fixed??? The seller has all of the re-build paper work & receipts & the engine starts & seems to run fine. What do you think??? Thank you!
Al

Answer
Now this is my personal opinion so do not leave a feed back calling me an idiot. I would head for the door and find another engine. What you see is the visible crack and you have no idea if there are any more hair line cracks hiding inside the block. Actually I believe that the machine shop technology and skill level of the machinists is not as good as it was 30 or 40 years ago. This is due to the fact that most auto service today is a "replace it rather than repair it" mentality. Back then we were doing engine block crack repair in our garage routinely but we never guaranteed the job. A decent 283 should not be that hard to find. If the engine was hard to find, like say for a 37 Cord then it is a different story. I did a block repair on one of those a short time ago, but no guarantee.