I'm not sure what you mean when you say.......unshourding the valves. .....Also opening the bowl areas.....
is that the same as port and polish?
I'll find some pics online. It's raining today, and I'm being lazy.
But, if you pull a valve out and look down into the bowl area, you will see sharp edges and 90* turns that will slow the air fuel mix down. You can knock off those sharp edges and lay those 90* turns down, makes it easier for the mix to travel into the combustion chamber. Air fuel mix is heavier then air, so it will slow down fast, keeping it moving (velocity) will make for a faster throttle response. The engine will be more snappy, and rev faster from idle to WOT, and every where in between.
Unshrounding the valves.
If you look at the combustion chamber closely, you will see how close the edge of the valve is to the sides of the chamber, in SOME areas. When the valve opens this area becomes closer, again slowing the air fuel mix.
NEVER open up the intake runner on these clone style heads. The intake runner is too big to begin with. Making the intake runner bigger, will make the engine feel lazy and throttle response is horrible.
Jus knock off left over casting flash and rough it up with sandpaper to help bust up (atomize) the air fuel mix. Smooth runners will cause the air/ fuel to separate and puddle when it's going thur the intake during low rpm. There's alot going on during the intake stroke, different temps, angles, vacuum, pulses, while the mix is headed to the combustion chamber.
I don't polish these heads, it's a waste of time, IMHO. I use Emory cloth or really fine sandpaper to clean up the chamber and get any imperfections, or any thing that can cause a hot spot, out.
I might get off my butt and get some pics of old heads I got.