My home inspection of Speedmaster heads
I guess my question was are they really 190 ports?. If you look at the flow numbers posted they are not great for being a 190 port, I realize other things can affect that but it seems possible they are smallish in size. When compared to a trickflow they seem to have allot of unfinished area as mentioned and I agree they could be big already in those areas due to the castings, really the only way to know for sure is to cc one. As far as the cnc work I was simply thinking of making the port bigger if needed not so much the finish.
It seems there are two schools of thought on surface finish depending on the application but I only have second hand knowledge of it and have no actual testing to back up either. I have for the most part left my intake ports carbide rough and semi polished the exhaust but I use a an electric die grinder with allot of speed and the ports are pretty smooth as finished. YR has chastised me for it a few times but I don't like messing with air any more!.