Originally Posted by randy snyder

From everthing I've tested I would have to stick by the non polished surfaces. On the Flow bench I ran a test by taking a motor and polishing the crank, case, liner so that everything was like pretty and shiny. I flowed it that way and then re-did the whole thing with about a 120 grit finish. It flowed better with the rough finish! So these days if someone wants a polish, I polish the top fin of the head!