Too Much Torque???

I am in the process of building up my car. I am putting on control arms in the rear right now. as I was underneath the car I noticed there were a few cracks in the floor pan (looks like cracks in the cement). It is right above where the driveshaft meets the diff (I can see up there because the driveshaft is oulled right now.) Could this be from torque twisting the body?
Thanks
:shrug:
 
I had 2 cracks there in my car along with a few under the seat also. This was all when I purchased the car and it was stock as a rock, also before the subframe connectors.

Just weld them up, and if you do not already have them install Subframe connectors.