GM-GMC: poor headlights, nighttime visibility, acceptable voltage

Question
I have a 1997 Chev 3500 4x4 truck with flat deck.  The problem I have is my headkights seem to be to dim (Not as bright as they should be).  I have tried several upgrade like installing multi-reflector headlamps and using 100W and 75W off road bulbs in these headlamps.  I checked the voltage output and it reads 14.2 V at battery and 12.0V at headlamp plug.  Any suggestions on what I can do to improve performance of lights.  Thanks

Answer
Although a 2.2v drop is [slightly] excessive from the battery to the headlamp plug, it isn't horrible.  Generally an acceptable voltage drop is .1 per connection, I would be surprised if there are more than a half dozen connection between the battery and the headlights, however, assuming that the electrical system is functioning properly the only recommendation that I could make would be to try buffing your headlamp lenses.  They can get cloudy or pitted from the abuse they are subjected to given their location.  There are kits that you can get at most parts dealers to renew the lenses, if they are as good as they claim they are, it should improve your nighttime visibility substaintially.
Hope this helps.