To power a half-ton 4x4 truck, an electric motor should ideally match the horsepower of the original gas engine for reliability. However, it may require slightly less horsepower due to electric motors providing maximum torque at startup, which is advantageous for moving heavy loads. A commonly suggested power rating is around 250 horsepower for effective performance. The comparison between electric and gas motors is complex, as torque characteristics differ significantly. Ultimately, selecting the right electric motor involves considering both horsepower and torque for optimal truck functionality.