AFR stands behind all of our advertised flow numbers (to account for production tolerances, we guarantee our numbers within 2% of advertised). While some of our competitors seem to take some liberties in that department, we try our best to meet or exceed all our published data. In fact, a handful of our products actually flow notably higher than we claim. A lot of engine builders rely on our heads to deliver the power they guarantee. It is important we provide them with a head that delivers and flows as promised every time. It’s also important to note that some manufacturer’s flow their heads on different types of equipment and conveniently don’t include that information in their test results. Cylinder head flow testing equipment is no different than dyno’s; some read higher than others and a few types of equipment tend to read a lot higher. All of our heads are tested on an accurately calibrated SF600, what most still consider to be the industry standard although the SF1020 has gained a lot of popularity in recent years as well. The newer 1020 benches read very close to an SF600 model while some of the older 1020 units were a little stingier. Note all our intake data is obtained using a proper fitting radius plate with the appropriate corner radius’s (clay is not consistent), and all our exhaust data is flowed thru a curved pipe that directly simulates a typical header installed in a production vehicle (a pipe about 10” long that has an immediate curve off the exhaust flange and straightens out).