Porting a slant six head

Here are some images Id like to add for reference. These are I believe belonging to user Fopar on slant.org site.

I thought that it was a no-no to polish the intake port like has been done? What do I know though.

What gains can be experienced by cleaning up the combustion chamber as has been done here? I thought for a street use engine that technically any time spent polishing is sorta wasted time cause the deposits build up pretty quickly.

These are 300 valves, Ill assume the larger version. I am not going to get this stupid with my head, only wanted to show the images for my next question.