Big horsepower 318 builds

Icetech said
I can't imagine that it would be THAT hard to do.. someone has to have ported a set, I know TF CNC ports them but they also leave large margins for safety (from breaking through, core shift and to avoid warranty issues).. 16cfm @.500 has to be possible...

I'm not a head porter so I don't know. I do know from having seen guys here porting and testing what changes yield increases in flow, a 20cfm jump seems like a pretty big deal, especially if you're already starting out with a refined head like the TF