You want to use a set of overkill $390 lifters instead of using $120 LS7s because you don't have the retainer (which is $12 from the dealer)?
Hmmm...
EDIT: It's GM part number 14101116.
EDIT x2: Use the Cloyes 3145/3146. I wouldn't trust a $48 timing set. The Cloyes includes a billet steel cam gear - the Lunati is iron.