does removing the valve guide boss (but leaving the guides) have a significant effect on wear of the guides. This would be for a regularly street drven car with a long duration (300-305 deg) and 1/2" lift cam.

It seems that removing it will really help air flow....but at what cost???

thanks for your experience

Berg preaches that the guide boss in the port should remain.

There are always "IFF's and BUT's to any rule...

but I would recommend to just stream line the boss as the best option,

unless the head comes from the factory with NO BOSS, as some do.

If you are cutting for std diameter dual springs it is wise to keep it in place,
to help hold the guide in place, and reducing the chance of it coming loose.

The flow gain of NO BOSS as opposed to a STREAMLINED BOSS is minimal,
and you may even increase flow for a given port size if the trailing web is shaped
like the tail of a tear drop.

This is how I see it, but there are may different views and options for discussion.