318 head porting for the average joe

Smooth is one thing, polished is another, this, is what I beileve your teach is thinking off.
The fuel will hit and crash and run down the pot and past the valve and form droplets, which do not fully burn. The un polished heads ports are consideed ruff and help stop this puddle running down the wall.

If your running a racey engine, then this need not apply. The metal can be polished glass smooth.

Ports/bowls should not be left with a surface so ruff that you can catch a finger nail on and tear it off like a far gone brake rotor.