How Much Damage could possibly occur..............

Every catastrophic failure is different. You pick up the pieces and see what's left.

You are asking an unrealistic question.
X2. Anything could be good or bad. You have to pull it apart to see. I've seen minor to major damage with the same part failure. I took apart a small block that had sucked a valve at about 7000 RPM and except for 2 rods every part was destroyed including the balancer and timing cover! I took apart another that sucked a valve at idle and didn't even hurt the piston or head. I've seen many slant 6's throw #6 rod right out throught the side of the block with enough force to break the starter off along with a chunk of the transmission. A lot depends on luck.