No sir.
A customer brought me that block to use as a foundation for a build. It was nasty dirty when I got it and still had the bearings in the mains. We stripped it down and then baked/tumbled the block. Cracks stood out like a sore thumb then.
I don't necessarily know if it was horsepower that split the mains, but since it was the middle 3 mains, the chances are high.
As you can tell, the feed holes have all been opened up, and instead of a blend at the mouth of the hole, they have been hit with a mill, which stepped the holes down....without any smooth transitions.
What stunk is that I had to call my customer and tell him that his prized possession S/O block that he had been saving for years was nothing but a paperweight.
Separate story....I had another guy bring me a block that had been machined. It had HUGE holes between the mains and the cam bearings. They were drilled and tapped for Holley jets. I told him there was no way I was going to use that block.