Those videos are getting old don't you think???
16v valve stem 6mm, 20v valve stem 5mm. This is one strong advantage, but you could always pay extra to custom make 6mm valve stem in the future.
Having less valves also make head mods like 3-angle cut cheaper and quicker to complete :)
If you read other forums, more and more going to 20v it's inevitable.
but please don't be fooled by 20v more powerful than 16v. It's only the case for BT, not SVT. Any 16v will be equal to SVT.
It is confirmed that extra valves does not make more power.
It is confirmed that 4 throttles does not make more power.
Careful optimization (eg BT vs. SVT) makes more power.
I always think BT is more power because it's TDC and BDC is different from SVT.
i.e. SVT 0-70
i.e. BT 35-35
see bill's website.