I assume the cam lift is mid .500s then, should have been no issue but either the rockers were not up to the task or there was unhappyness in the valvetrain.What do the others look like, seems that the alum was soft.

I run special harland sharp shafts on my car with .794 .747 lift mech roller with 260 seat 700 open springs. This year was the 2nd drag week on them with no issue. 1st year I was running st harland sharp rockers and they broke at the pushrod side, sent them back and had the geometry changed.

On a side note, my cam lashes at .028, for drag week I set it at .015 so there is less hammering.