I would go with the 2002 or later LS6 springs since they will handle more lift. Pushrods are a weak link so some hardened pushrods would be alot better than stock if you can afford the extra money. The stock reatiners are good for the LS6 cam but titanium is always better. It all depends on how much money you are going to spend. You already have 7.4 pushrods in the 5.3 so I wouldn't buy a new set of factory one's unless yours are worn.