Which 264? If you are refering to the HKS Step 1 264, then no, you will not need valve springs. If you are refering to HKS Step 2 264, then you will need valve springs. Either way you should go with rocker arm stoppers. If you are shopping around for valve springs, you might well do retainers at the same time. If that's an option you are going with, look into getting some BC (Brian Crower) valve spring and retainer set, the price are rather reasonable.