CNC Porting- The Best?

[Bob Eyres]

Since the advent of computer aided porting has happened since the introduction of the LT5, I would have expected that in recent years programs to have been developed that greatly improved the breathing of our engines. Programs that would be far superior and repeatable over the hit or miss results of porting by hand. Yet it seems as though many LT5's still get ported manually. Why is this?

You would think that, over time, ideal programs would have been developed for relatively stock engines, as well as moderate, and big displacement LT5's. Programs that would perfectly match the 16 separate runners in ways far superior to hand grinding. Not to mention all the other operations applied to the heads and other parts in the air stream.

Can someone school me as to why this seems to still be such a "black art" rather than an easily predictable upgrade?