First of all shops have a certin price more then they do an hourly rate. They are not going to time the guy and charge you for that. But if he does run into a problem they will charge for the extra time. Most places that had online prices showed that its around 250 for upper head work labor and around 500 for lower bottom end work labor. Now you are not really going into the bottom end, but you are going past just doing head work. So im pretty sure its going to be more then 250 but under 500. probley 350-375 ish
I dont know what your horly rate is in your area, but they all are going to be a bit different, and you'll also find that the amount of hours to do it will all be a little different depending on who you ask.
Me doing it at home will take a probley a full day, with a few beer breaks. If i was in the shop with my tools and lifts and such, I probley could do the piston, oil change and stage one cam in around 2-2.5 hours. No remaping or tuning. The shop will charge atleast 5-6 tho. I usally find that the book or standard time to charge is almost double the actual time to do the job. That is also if you didnt have to stop and do other tasks during that time (which i find never happens in a shop). (well at home too. beer)