Alaska Bowhunting Supply has some very valuable information.  Click the following links for more information. 
Top 12 Arrow Penetration Enhancing Factors
The Power of Momentum
I used this information to build my arrows for a moose hunt in September. Here is what I built. 

GrizzlyStik Momentum U-FOC 250 cut to 28 inches
Monarch 200 grain forged single bevel broad head
20 grain brass adapter weights added to the insert
4″ Gateway feathers right helical fletch
Total weight is 650 grains with a 23% FOC I’m shooting a Mathews NO CAM HTR set at 70 lbs. and 28″ draw.
According to OnTarget2 my momentum will be .615 at 20 yards. OnTarget2 is software that will help you determine the correct spine for any bow and arrow combination you can think of. I’m not even going to post K.E. because it has nothing to do with arrow penetration. The bow companies would like for you to believe that K.E. determines how much penetration an arrow gets. The most important aspect of this arrow is that it weighs 650 grains. Dr. Ashby has determined that 650 grains is the bone breaking threshold. Speaking of 650 grains you should check out the 650 challenge

I know people are going to freak out when they hear 650 grains. OMG you will never be able to hit anything with an arrow that heavy. Most arguments you hear about the light fast arrows revolve around “flat trajectory”. With all the sophisticated range finders on the market it really makes yardage judgment a moot point. Now if you’re just shooting foam targets then by all means shoot the lightest and fastest arrow you can build. For hunting I’m not worried about hitting the 12 ring. For most big game animals you have at least a 6″ circle to make a perfect shot. Also when you consider most shots are 20 yards or less the flat trajectory becomes even less valid. There has been a very bad trend happening in bowhunting. Taking longer and longer shots up to and including 100 yards. This is bowhunting not rifle hunting. One of the most rewarding aspects of bowhunting is getting close.

In my opinion the whole light fast arrow just doesn’t work. As a guide for Illinois Trophy Bowhunters I’ve seen these light fast arrows fail on numerous occasions especially when they hit bone. This is an actual quote from one of my hunters “It ricocheted off his shoulder”.  I know what you’re thinking. It’s all about shot placement. To some extent it is but bad shots happen and when they do I want an arrow that will penetrate bone. Even standing in the yard practicing we all occasionally make a bad shot. Hope for the best but prepare for the worst. 

Do yourself a favor and read the Ashby reports It’s the only scientific study I know of about arrow penetration. I can’t stress the word scientific enough. We’ve all seen the so called broadhead tests but you have to remember these are usually backed by the broadhead companies. So surprise guess what their conclusions are going to be. Plus you can’t evaluate the performance of a broadhead on anything but animal tissue and bone. Most of these tests are done in ballistic gel.