If you already have Jesel rocker arms and you just need the heads machined then send the heads and the arms down to Jesel and they'll take care of it for you. I'm sure there are plenty of other shops who can also handle the machine work. I machined my EZ heads for Jesel rocker arms but I had access to a good machine shop. I will say that it is better to order the heads from Indy with the Jesel machining rather than reworking single shaft heads. Doing the work once is much better than drilling and tapping holes that have already been drilled and tapped.