If you have a later 979 (at least the second gen) it most likely will need an ISO.BSC (English) sized headset. My 85 Carbone that uses pretty much the same head tube section as the 979s has a BSC headset and my BB shell is also threaded English. I think there were older 979s that did have French threading and headset size, and I suspect those were pre-85 frames. Only way to be sure is to measure the head tube opening with calipers. Your LBS can do that for you if you do not have calipers. Sheldon brown should have the different measurements for headset standards on his site. The better determinant of course is the threading on the steerer tube as you will know right away what headset you need if you test it with a headset locknut you know is a French or an English threaded headset, but note that Italian and English headset locknuts can be interchanged because their thread size is close enough.

A nice headset to put on the 979s would be the French made Stronglight's model A9 headset. You can still find the older needle bearing version NOS once in a while at eBay, but you will have to pay quite a bit for them. Easily over 70 bucks. You can also opt to get the new version of the headset that has sealed ball bearing cartridges on it. I have one on one of my bikes and its working very well. If you want a bargain version of a needle bearing headset, check out Miche's model Primato, which is pretty much a direct copy of Stronglight's needle bearing headsets. A bargain at under 40 bucks sometimes, brand new! I have the Primato on one of my other bikes too, and it's working just as well as my Stronglights.

Chombi