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Hand porting and porters is becoming a "lost art". CNC programers copy and use a hand ported head as a blueprint good or bad. I reworked a set of AFR cnc'd chevy heads that weren't worth crap and WAY off their advertized flow numbers. Hand porting is NOT easy work.

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yes you can start with ports on a head that have been digitized. Then use that digitized model as your "blueprint".
A good machinist/programmer will go in and alter that model to make it better. Then keeps changing it as the data comes in and logs the data to what works and doesn't to better the head.