couple of reasons...crank twist and belt deflection. Mark says its the way to go on a WOT high rpm drag car...im just doing as im told by the master. Its no fluke he's the 3rd fastest in the world, his car is ultra consistent and reliable. The custom set-up does not use a tooth style trigger wheel mounted on the nose of the crank...its nice and stealthy. Im sure Shane knows the set-up im refering to.