Think this through. If the timing belt broke, there would no longer be any tension on the cam sprocket and therefore it couldn't shatter as a result of the broken belt. A much more likely scenario is that the cam seized and the cam sprocket shattered. You wil probably find that the belt is not broken. If that is the case, let me know as I have several of those heads sitting in my shed ready to be mounted to your block. Even if the heads were damaged due to a broken belt, a set of heads will be cheaper than rebuilding yours. If the cam seized, you won't be able to rehab the bad head.
I hope I am wrong, but I wanted to give you another repair option;
Where are you located exactly, the northeast is pretty big.