Yes, but you may be lacking in the momentum department. KE is figured at the bow, not down range. A heavier arrow would retain that speed longer. A light arrow will slow down quickly. While 70# of KE is good, and will probably kill anything you would shoot at.

I am not sure what formula you put up, I've never seen it, but that's no indicator of anything except that I've never seen it. KE=speed x speed x weight / 450,240.