What are the practical limits to the stock Magnum Rocker package?

Thanks guys...I really have been thinking about that cam. I'm not sure it is in my best interests...I am not looking for all out max hp, but rather near OE reliability and daily driver capable. Hell didnt the 380 horse magnum crate use a 509 cam? I guess the roller just gives you so much more capability for lift, the engine guys feel you have to use it. So I am still unclear...will the heads need much work on the spring seats and guides to run a cam that big and the appropriate springs?