Recommend any heavy duty chew toys for PitBull?

Go to your local pet store. They'll have some good ideas. The old toys might have been destroyed partially due to their age and not to the quality of the toy. Rubber will naturally start to deteriorate after a few years. (I like the Kong toys.) You may try Bully Sticks--it looks kind of like rawhide, but it isn't. It's made of beef tendon that's been dried up and is supposed to be gentler on your dog's stomach.