What makes you think the cam is worn out, or "worn into these lifters"? If you've got it apart, the thing to do is measure everything. .... Your question doesn't make sense to me. Why wouldn't you be able to "replace all the lifters and use the stock cam"? But then the question is: why would you do that? If your lifters are ticking it could be an oiling problem, like a dented oil pan, or an old, low oil pressure engine.
