[Rich Biebel]

Junk casting...

If you don't use a hardened washer under the bolt or nut if it's a stud the casting can do exactly what you have shown in your picture.

Old Small block Chevy heads used to do the same thing.

Poor casting material.....head bolts with no washers...

Short head bolt bosses on 461 heads often split and had broken sections just like that pump...

The factory used to even weld repair some heads and blocks with minor imperfections like that.