porting

I know this sound like a daft question. However what are peoples opinion on what this should involve ? e.g. Enlarging of ports Knife edgeing the channels Smooth out the casting Anything else? Cheers

I've built the engine now, scat rods etc, and have a set of supertech valves (thanks bill). The exhaust outlet is smaller than the manifold so there is a lip, do I need to match the port to the manifold to help flow? Other wise is there a great benefit to getting the head professionally...