These are procomp/speedmaster 170 as cast. I did a moderately decent Port job on them here at the house. I used brass tubing to sleeve the push rod tunnels, and ground away all of the aluminum to open the pushrod pinch until I hit the brass. Worked on the roof and the sides, took the ridge off of the short turn, and that's about as far as I went. As far as how much it flows, I don't have a flow bench so that's all guess work at this point.