how much will they take

Depends on the center section your using. That being said if you break it and the rear housing is a stock a body unit, Id sell it and just buy a Dana 60. If (by some dumb luck) you break the Dana 60, your pretty much done with cars are you can buy Rockwell axle (and go luck getting that axle in the car! Take pictures if you do because I wanna see that!!!!).