As an example, if the cylinder head flows 275 cfm @ 28 inches of water, and with the intake manifold and carburetor it only flows 206 cfm, a 25 percent flow loss is present.

Each head is carefully placed on the SuperFlow 600 flow bench and tested from 0.050-inch to 0.0700-inch valve lift. In most cases, the heads were tested twice to ensure the accuracy of the flow ...

Note that the difference between the boiler feed pump head-flow curve and the system resistance curve (Figure 1) provides the basis for the pressure drop available for the drum level control valve.

The highest flowing head may not perform the best if it only flows 10 more peak cfm of air, but has worse low- and mid-lift flow and is 30ccs larger than a different design, which is smaller and ...