I recon its impossible to make the surface completly smooth, I spend hours polishing mine, and still it wasnt as smooth as this photo. But it doesnt matter now, my car was written off this arvo.

there's some material removed from in front of the valve guide. In standard ports you'll see a big lump of alloy in front of the guide.

There's also some material removed behind the guide, in what they call the valve pocket area. It's in the port at the top of the pic, pretty much all the way around the top 1/3 of the circumference of the valve seat, inside the port. Hard to really see the difference without a before pic I guess...

And yes, we left the port a little rough. Combustion chamber is polished with some folded up emery tape on an electric drill, using a fitting that's designed to hold a sanding disc. Dodgy backyard technology, but it worked OK. No fancy tools used apart from 1 carbide cutting tool used in the ports. Polished chambers reduce carbon build up, and smooth off all distinct edges, both of which can be hot spots and cause detonation.

Are these done by hand or machined? Also nice polish job.