The 2003 chassis is 16.5 inches too long. The way this frame is built, they slid the front part of the frame into the rear. So all they had to do was make one front frame that fits everything, and GM could slide in a longbed frame, or a shortbed, or a crewcab etc. in the rear. All I did was remove the factory weld where the front and rear frames join and sepperated it.
