[dennisw]

http://www.mapawatt.com/2009/07/19/bicycle-power-how-many-watts-can-you-produce

Here is a good breakdown on how much watts and horsepower a very strong cyclist can produce. Over a sustained effort of one hour 430 watts was what one cyclist was producing

1 hp(E) = 746 W http://www.rapidtables.com/convert/power/hp-to-watt.htm

****** My mistake was thinking horses produce at the rate of one horsepower when actually they are capable of higher outputs over a short period. At the race track over a two minute race maybe they are producing at 5-10 horsepower

[Paladin2]

There was an article in Scientific American (way back when it was about Science) that had a plot of human output measured using cyclists and intended to get a handle on the design constraints on human powered flight.

I couldn't find it online in a cursory search.

The human body seems to differ greatly from a reciprocating internal combustion engine powered auto.