Alternator bracket bots broke off!

[SEVENTY1]

350 short block

I was driving to work this past friday, and i noticed that my temperature started to go up. I got off my truck and popped the hood to find the whole alternator/alternator bracket completely loose. All the bolts broke off!

It seems that the bracket has three bolts holding the alternator in place. Two of the bolts bolt up to the block, and the other one bolts up somewhere else. Is this right? It seems to fragile to handle the torque from the engine, I dont know what could have happened. I had the engine rebuilt about 400 miles ago. Has anyone ever had this problem? I dont know if the shop installed it correctly, does anyone have pics of how the bracket goes?

Any help or suggestion is appreciated.

Also how would I remove the remaining bolts that stayed in the block? Is there a tool that can help me remove them?

Thanks