My machinist charged $220 to install the 1.75/1.5 valves in my OEM head. This included the seals, the hardened seats, but not the valves. I think that was a pretty reasonable price. I bought the valves from CI and I forget how much that was, but you can look them up and do the math.
The porting and polishing was done before I bought the head, but the guy did it himself so It didn't cost much. It had already been milled too.
Harry