I bought mine locally, ran into 2 with cracked mains at the main bolt hole, both cracked were at #4 and one on #2 main. Check close. Luckily the deal I have with the guy is I give him his price for std bore blocks and if they are bad, I eat a clean and mag but he refunds me.
If you can live with a ribbed block, may be able to grab another. Shoot me a PM. Also have access to a .030 C-scratch with big bolt rods, but I haven't grabbed it because its a short block and the guy wants a little more for it.