The answer to how many CCs equal one horsepower can only be estimated at 1HP per 15-25 CCs. There are too many variables to enable an exact calculation.
Horse Power is a term invented by James Watt, who also invented the light bulb. He calculated that a horse could do, on average, 33,000 foot pounds a minute. The calculation of CCs varies on the condition of the engine (rmp, turbo, tuning). A torque, which is a force that rotates, is also measured in foot pounds and is another variable that needs to be considered into the calculation of CCs in a car.