The gearbox of the engine was moved from the bottom of the engine to the side. The gearbox makes the engine look a bit like a triangle. Since the engine is close to the ground, it is possible that they can be damaged by things lying on the ground. The CFM56-7 engine on the 737 Next Generation burns even less fuel than the engines on the 737 Classics. The Boeing 737 MAX aircraft will have CFM International LEAP-1B engines. These engines are supposed to burn 10-12% less fuel than the CFM56-7B engines on the 737 Next Generation family.