Matt makes a very valid point. Also when it comes to KE, bows which are maxed out have a set amount of KE unless extreme variables are taken in arrow weight. The best way to increase KE out of a bow is to increase poundage. IF your bow is maxed out, one can usually tweak a bow and gain a few extra pounds without damage to the bow. This is done with twisting the cable(s)/string but make sure to check you tiller and cam(s) timing nock travel and tuning.

When you increase arrow weight with the same poundage, you decrease the speed of the arrow thusly in the formula, KE stays relatively the same. The opposite is true if you decrease arrow weight, you gain a little speed thusly retaining about the same KE. When extremes are taken in weight in either direction is when KE can be manipulated.

If you can tweak a few pounds and increase arrow weight, your KE should climb a little. It is recommended that one use 45 ftlbs of KE for whitetail sized animals and 55 ftlbs. of KE for elk sized animals tho in history, many animals have been taken with less. A good hit is the most important agenda for lower KE shooters and marginal shots are absolutely off limits.

Again, on Matt' s recommendation alone, you arrow shaft selection should be reconsidered.