I've read that it's not best solution to have very smooth finish on
intake ports because fuel don't get mixed well with air if it's too
smooth.

How do you finish intake ports?
Using cartridge rolls (standard abrasives) looks very smooth or is
that rough enough?

 

I think I went to 120 grit rolls in the intakes and polished the exhaust ports. Too smooth(intake) is a problem for a carbed motor, not so much for fuel injected.

EDIT

Had a peak at my rolls, it was 80 I used on the intakes and 120 on the exhausts. I then used scotch-brite and light oil to finish off the exhausts.

 

Different head porters used different finishes depending on the cyl head material and the engines application. Ask any number of head porters and you will get any number of answers as to excally what finish they use, if they will even tell you.

As a general rule, I personally belive that the intake port finish should have some "texture" to it. You can use different fineness of port wall finishes to exasperate all kinds of effects in a port. For example, If you are careful you can promote better swirl (if your port shape promotes any at all) in the combustion chamber by paying attention to how the final finish is applied with a cartrige roll at the bowl under the valve in the intake port.

The exhuast port and combustion chamber should be as smooth and finely finished as possible to reduce the surface area where carbon could stick to the surface.

I use 80 grit finish on alum intake ports with medium to heavy pressure on the grinder, I go one step further and use a "cross buff" to get a very fine finish on my drag engine exhaust ports and combustion chambers. Street cars and oval track engines get 80 grit and very light pressure here.

Cast iron is another ball game entirely. Unless you use a brick to finish cast iron, it is going to look like glass. I generally use 60 grit on intake ports and 80 grit on exhuast ports, but some class engines get pretty exotic stuff done to them that dosen't apply to general competition or street car engines.
Will

 

I think you can go smooth on the intake port runner because fuel is injected onto the back of the valve but pay attention to the shape (proportion) of the bowl to keep it pretty much the same as original. This is where the swirl is generated and the stock Vette Al heads has pretty good swirl already.

In the chamber a smooth but divit finish is desired, along with unshrouding the intake valve and dressing the spark plug boss.

If you can order books from Amazon.com, David Vizard has a great book on porting & working the Vette Al heads. If interested the ISBN number is: 1-884089-34-8.

 

Thanks!