First, simply going to a heavier head will NOT increase your kinetic energy. A bow will store a certain ammount of energy at a given draw weight and draw length give or take a small ammount. When you arrow gets heavier your speed goes down thus offsetting each other and your KE stays the same. It may change a small ammount, 1 or 2 foot pounds, when a signifigant weight change is made to your arrow but not 25 grains.

What will increase is the arrows momentum. 25 grains will not do much but it will increase a little.

The only sure fire way to increase your KE is to speed up your current arrow or to use a heavier arrow and maintain your current speed. You can up your poundage, increase your draw length, loose some string accessories, or use a lighter and stiffer string. Making sure that your bow is perfectly tuned and operating at its optimum efficiency will also add a couple of FPS thus increasing your KE and momentum slightly.