well said, I dont ee how different shapes will get you better flow. I know that shops dont do as much as you think. they just dermo it out and might put it on a flowbench if you get some one good.

 

You don't see how a straight piece of pipe will flow better than one with 90 degree turn in it?

 

Ok this is where everyone thinks bigger is better....its not true. Bigger ports will not always give you more power. With the way a 4 stroke works, a big part of your high end gains are based on velocity of the incoming air. Think of it, a high profile cam makes your motor idle like crap.. this is because your incoming air velocity is too low at idle RPMs. The bore/stroke displaces the same amount of space right at idle as it does at 9000 rpm right? so why does this cam make more power at higher RPMs? The same theory can be used any any RPM range. Your intake valves(s) are still open when the piston is on its way back UP.. how can this be? this is because the velocity of the air is so high that it pulls more charge in, even when the piston is starting to push back. You can't just hook your head up to a flow bench and look for the highest numbers. The profile of your cam and the size of your valves all play a major part. In fact, most heads flow more than enough.. they just need to be fine tuned. Some of the best tuners will even make the ports smaller to boost power in the engine's peak RPM range. The same tuners also prefer to ruff up ports to add turbulence in the air/fuel mix.