Exhaust Flow: Volume verses Velocity

[Fendamonky]

So I was thinking...

When it comes to power and response which is better? Exhaust flow velocity, or exhaust flow volume?

Obviously there will be pro's and con's to both, I was hoping that the more knowledgeable and experienced minds here would be willing to share some information.

The reason I got to thinking about it was because I've seen some reputable shops that will leave the exhaust ports stock for "ported" engines. I figure there has to be a reason for that and thought it might boil down to volume verses velocity.

I have my thoughts, and my ideas which feel right in my head, but I know that I'm relatively uneducated in the realm of engineering and flow characteristics.

So please, share your educated opinions!

Cheers,

Levi