Highest flowing sbm heads?

Thinking of it as an air pump may be helpful in finding more power. But pumping the same amount of air doesn't necessarily equal making the same amount of power between two engines. You still have combustion to deal with and many other things that affect how much power is produced. While they may be helpful flowbench numbers for the cylinder head are only flowing air (without fuel), at a steady speed and in one direction. According to poeple smarter than me thats not how it works in a running engine. So while thinking of an engine as an air pump may be an oversimplification. It still can be a helpful way to think of it.