I wouldn't be suprised that the tail shaft and main case is cast steel, not cast grey iron If so you can have it welded You need to make sure that the drivshaft doesn't bottom out, slide the trans yoke in all the way and then slide it out 1 to 1 1/2 inches, that should be the center of U joint to center of U joint length needed to avoid future problems, make sure the car is sitting with the suspension loaded, not hanging down off of jackkstands under the sub frames