I thought about the 416 kit for my 400EX. However after thinking about the performance I might be able to get with just a drop in cam. I do all kinds of riding and I was thinking about the drop in WB all around cam. Can I still use stock rocker arms and vavle springs and seals with this cam? What can I expect with just the cam? I still want to leave my options open for the 416 later one. I just want to keep my motor dependable.