Yeah I dyno them, and have flow benched a set or two as well as others. As well as 1000s of other people. There is no black magic. Facts are FACTS they make HP & TORQUE and lots of it
No one said they were the best but they are one of the best cylinder heads that retain stock valve angles and stock hardware.
AFRs are all about velocity & torque and they always have been. Find me another cylinder head that makes 425+ hp at the rear wheels with a small 224°/228° camshaft and still has excellent street manners and lots of torque everywhere