Based on the definition of horse power I would say between 275 and 550 pounds.
http://www.yourdictionary.com/horsepowerHorsepower is defined as the power that a horse gives when pulling, and it is used informally to mean power, or is the power needed to raise 550 pounds a distance of one foot in one second or the power needed to move 33,000 pounds a distance of one foot in one minute.
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http://www.yourdictionary.com/horsepowe ... 0e5sVtc.99https://www.britannica.com/science/horsepowerHorsepower, the common unit of power; i.e., the rate at which work is done. In the British Imperial System, one horsepower equals 33,000 foot-pounds of work per minute—that is, the power necessary to lift a total mass of 33,000 pounds one foot in one minute. This value was adopted by the Scottish engineer James Watt in the late 18th century, after experiments with strong dray horses, and is actually about 50 percent more than the rate that an average horse can sustain for a working day. The electrical equivalent of one horsepower is 746 watts in the International System of Units (SI), and the heat equivalent is 2,545 BTU (British Thermal Units) per hour. Another unit of power is the metric horsepower, which equals 4,500 kilogram-metres per minute (32,549 foot-pounds per minute), or 0.9863 horsepower.