The present invention relates to a high overlap camshaft for improved engine efficiency. A vehicle may include a drive axle, an engine assembly, a coupling device, and an engine load management system. The engine assembly may include a valvetrain including a fixed-lobe camshaft and intake and exhaust valves supported by the engine assembly. The fixed-lobe camshaft may include a first lobe engagedwith the intake valve to open the intake valve and a second lobe engaged with the exhaust valve to open the exhaust valve. The first and second lobes may be fixed relative to one another to define a constant valve overlap condition that provides for opening of the intake valve before the exhaust valve is fully closed, creating an engine operating condition that results in combustion instability below an engine load limit. The engine load management system may be in communication with the engine to prevent engine operation below the engine load limit.