Dang...

I would agree with the split cylinders causing the engine to hydraulic and come apart. Kinda surprised it does not happen more.
After sonic testing a smaller sample of small blocks and big blocks I would never bore more than necessary. The engine is only as strong as it's thinnest cylinder.
I would think the modern hemis would have more uniform casted cylinders? Maybe not as thick as the older LA blocks but less thin spots. That's just my assumption.
If I had a garage full of the newer hemis I would go that route. Start building that BGE block to an actual 600 HP.