Small block engines only have 3 ports because of most race sanctioning bodies. You will find that this is completely opposite for larger engines though. It is often thought that the more ports your engine has the more powerful your engine is, but this is always true. For instance, a 3 port engine might have less ports than an 8 port engine, but if the 3 port engine has much larger ports outweighing the 8 ports than the 3 port engine will be faster. Ports are just ports to carry the fuel/air mixture from the crankcase to the cylinder.

Don't look at the HP numbers of an engine. Remember the old saying "Horsepower sells cars, torque wins races''? Most engine manufacturers fudge their engine numbers and all engine dynos will have differenr results from one another. If you dynoed a .12 it may read only 0.70hp, but if you connected it to another dyno then it might read 1.10hp.

OS engines are good because they underestimate their engine's horsepower.

Sean