"Picture the bottom sides of the block, near the center. One side had an allen head bolt, other side was a 5/8" bolt. The crack surrounds the 5/8" bolt housing."
You're describing the coolant drain plug hole. It's a 1/4" pipe thread. That's an easy fix for anyone who can use an acetyline torch and a brazing rod. Find the end of the crack(s) and drill a small hole to prevent it from spreading any further. V-groove the crack with a die grinder, and have a good welder patch it with brass. It only has to hold coolant, and cooling system pressure isn't nearly as hard to seal as oil pressure or compression. That's definitely not a reason to scrap a good block.
Jerry
