Harry,
Looks like you and I are in the same boat rebuilding our engines. Have you measured your head or checked for flatness yet? If you have dial calipers, a framing square and feeler gauges you can get at least a rough idea of what your head will need done. Measure the overall thickness 3 placed around each side, 6 total. Then use the straight edge and feeler on the bottom to see if there is warpage. The spec is .1mm out of flat. My head is slightly warped on the bottom, but the top is curved. It was surfaced on the bottom years ago, but not the top. If you dont have these tools the machine shop can take all these measurements for you and then decide what needs to be done. Just make sure your shop really understand what needs to be done as the average Joe valve job just wont work. If you grind the valves and seats you are also removing some ability to set the correct valve lash. How many threads are left exposed on the ball studs? You need to make sure you can properly achieve correct valve clearances and be sure your cam is not binding. If you cant turn it easily (with the rocker arms removed) with 2 fingers then you have issues.
Are your ball studs worn? Do they have a little nib on top where they wore into the rocker arm? If worn too much you should replace the ball and the rockers, but note that this will again decrease you ability to adjust the valve lash. You can buy just the upper part of the ball stud from msclassics.de 180-050-05-74 as well as a lot of other engine parts. If you reuse them, then yes keep them in order.
You only need to remove everything from the top if the top of head has to be milled. For a normal valve job you can leave the ball studs where they are. Removing the locating pins and studs and valve guides is best left up to the machine shop. From what I have read the overall head thickness is suppose to be 84.8-85mm -1mm max.
If you mill the top and bottom you will need shims under the cam towers to compensate. Take a look at my post to see what I plan on doing.
