Horsepower is just Torque over time. I mean that literally as Horsepower is a metric derived from the engine torque. There are two ways to make power, displacement or RPM. A smaller engine can make just as much power as a larger one by increasing the amount of time (RPM) the power is made. Look at Formula One cars that have tiny engines but huge output. This is done now with turbo chargers, but some years ago they just did it by revving V12's, V10's, and V8's to 18,000+ RPM. The same way a tiny motorcycle engine can make over 200 HP naturally aspirated, by revving to the moon. Larger displacement can make the same power at much lower RPM, but larger engines also have more rotating mass and usually the inertia is too much to overcome and they cannot rev very high anyway. The big block American V8's of the 60's usually made about the same power as the smaller displacement small block V8's used in Can Am racing, but didn't rev nearly as high. It generally just ins't cost effective to put racing style engines in everything, despite how much we wish that to be.
