Hi tabetha,

I had heard similar about ‘polished’ surfaces but I thought that was more to do with fuel atomization in the port area.

I am not really thinking of a mirror finish, I just want to get rid of some of the snotty casting lumps as the finish is really bad. If its not good to get rid of the central web I will knife edge it as it is quite wide and also very lumpy

I was thinking of a finish like in the throats of my head. They look like they have been finished with a emory paper flap wheel i.e. lots of small lines / scratches but smooth to the touch.

I did the same thing in the inlet trumpets as the seam in the casting was about 3mm proud in some places