if its true that the heads were bad from the factory, and DD isn't going to warranty any of it, then a class action suit should be filed.
but, the question was already asked, was it the factory that said this, or the repair shop you went to said this.............
now, if its a DD authorized shop, or the dealer itself, then they pretty much admitted fault.
right now, i don't know of anyone with the same problem, and the DD engined truck i ran only had a coolant tube problem. that tube runs along the top of the engine. it was a very simple fix, no down time required.