Which spark plugs?

I think that N6Y's were superseded (or at least "replaced by") N7Y. I also think the early 2000TC decals did specify N6Y's, but the later models had the decal specifying N7Y's (certainly the old UK J reg 2000TC we scrapped had N7Y's on the decal)

Maybe someone could confirm/agree/partially agree/totally deny... this?
This is an old thread, so my apologies for re-awakening it, but I ran across it while looking for the proper plugs to put in my early 2000TC, and as it happens, I can confirm that the early TCs did come with a label specifying Champion N-6Y plugs:



Well-Known Member
Again waking a dormant thread. I went on the Champion website the other day as I'm getting new plugs for my 2000TC. Champion now list N9Y as the correct plugs. I know Rover changed spec from N6Y to N7Y in the early 70's. Anybody have an idea if the hotter plugs are ok? Any issues with pinking?