I agree with the stud suggestion. Obviously some Azz-clown replaced the oil pump once in that engine and didn't have it fully seated. Red Lock-tite the stud. If you know or can find someone who can weld cast iron have them spot weld that cracked piece for peace of mind. But if the threaded hole goes quite a bit below the cracked area you will be fine
Common first time error. At least when installing from underneath the vehicle. Although when I did it, cracked the oil pump. I think that's the most common breakage when the nose isn't fully seated.
