Our flow numbers are gathered are from dozens of tests on each particular head. After many tests are completed and the data is attained, the flow figures are averaged to achieve a baseline.

It is true that some ports on a particular casting may flow 2 to 4 percent more than our average base line. However, the next port (or the next head) may be down more than 4 percent. This is especially true with stock cast iron cylinder head castings.  Also, the head’s flow numbers may change over years due to changes in production.

All of our flow testing is performed at 28” of water with a SuperFlow 600 flow bench, Flow Pro software from Audi Technology and the flow bench equipment displayed in our catalog.