Min:

The ratio is 3:50. A 50cc engine is 3 cid, an engine of 0.15cid is 2.5cc.

Going between 2s and 4s is more complex. The two stroke engine usually can turn a lot more rpm than the 4s, rpm generally equals horsepower. But the two stroke does not get to use its entire displacement for power, the effective displacement, from the time the cylinder ports close is about 30%-40% less than the numeric displacement. And the effective stroke is reduced as well. Again a generality, longer stroke means higher torque.

So, the two stroke wins the horespower side, the four stroke wins the torque race. Then add the note that the peak horsepower of the 2s is often at an impractically high rpm, we have to decide the only place the four stroke engine loses is in a racing plane. The 4s also loses the price war, but that's outside our consideration of the moment.

Bill.