I guess I am trying to determine if it is necessary to buy the LT4 keys and retainers or if I can just reuse the stock ones? I dont see keys and retainers going bad with old age, but I really dont know.

 

The retainers from the LT1 springs can be used with the LT4s without problems. The dia. of the spring retaining area of the retainer is the same. The LT1 retainer, cuz it is thicker, in the spring retaining area, acually does a better job of containing the spring. The LT4 retainer, cuz it IS thinner, (in the cap/spring retaining top portion only, not the keeper area) WILL be lighter than the LT1 retainers. Keepers are the same.