Good Cleveland blocks around here are like the proverbial hen's teeth, except there might be a few blocks still around, unlike hen's teeth! I once had a J code block, but sold it believing it was no good with rear drain holes. I also had an L block, but it had been cracked and welded, so I got rid of that one too. Now I can't find a good untouched block anywhere local.
That new block looks interesting. I wonder what the finished cost will be.