For that draw weight a nice Ace standard 125 grain head that is razor sharp. They have a wide cutting diameter and are easy to sharpen.

One thing you may need to consider is your total arrow weight. If you are drawing 45#'s then the total arrow weight should be no less than 400 grains. The heavier the better, 450 to 500 grains. It is the arrow weight, with a razor broadhead, that produces maximum penetration.