When I see BIG starting numbers like this it raises LOTS of questions about flow bench calibrations.
.100...............73...........................73
.200..............151..........................152
.300..............214..........................218
.400..............245..........................267
.500..............262..........................308
.600..............276..........................337
.700..............281..........................346
I have had a lot of Stealth heads on my bench and when I test I test EVERY port on every head. The most I have ever seen was 267cfm. Start with high numbers end with high numbers and those in the know, know better.
This! ^^^
I look at it this way: I see 9 out of 10 very good head porters have results within 10 cfm of each other. Then I see one guy with results that are nearly double that of the other guys. Who is the outlier? Or, am I to believe that Dwayne and the other head guys here are a bunch of know-nothing hacks?
I had Jeff's/MCH Eddy's checked on a local bench and the numbers were within 1 cfm of each other. Trust, but always verify.
Not all flow benches are the exact same on results, same on the operators sometimes also 
In other words if the heads flow 200 CFM will they only make 400 HP regardless of the C.I. or does it mean that those heads on a 300 C.I. motor will make 600 HP 
