Again its a visual thing guys.
5 angle standard VJ is 15,30,45,60,75 degrees.
This helps the air flow transition over the valve and seat.
A standard VJ dosen't help alot(5%) but a Race VJ helps up to 30% on flow.
As for bigger valves doesn't always help , as a matter of fact sometimes it kills power.
Porting is like anything else , You can learn how to paint but will never be a Picasso!
Anyone can port but only a few can make tons of power!
Its the same for paintings , You can't sell your painting at the same price as Picasso's painting.
Remember this when shopping around for porting jobs !
You get what you pay for so don't think you get a head that flows good for 200-750 cause you are actually getting a looks good but don't work and we have a Flowbench to back up what we preech!
We welcome anyone to test their heads and see for themselves what real flow is all about!