Thanks tvcreative--I thought about those but am trying to be exact, period correct OEM on this build, so I believe the Strong and XC are my only true choices other than an SR Laprade (BMX or MTB). I have one NOS Suntour XC but two 85 frames. I have a TCO and Laprade in the right size, but both are pretty worn and marked.
Interesting point on the American Classics posts that I was told by an old employee. The earliest ones for MTBs (guessing late 85-87ish ?) used the same thickness of post tubing as the road version from the time (which were shorter in length). There were a lot of failures due to this thin tubing and longer length on the MTBs. If you are considering using one of the posts from that era, try and use a road version if it fits rather than the MTB. I don't know when the issue was corrected but eventually it was (and I'm not sure there was little, if any, difference in the cosmetics for awhile during that time). I had a friend around that mid-80s period who tried two of the posts when they first were introduced. Both bent/broke in half during off road rides after little use and he (and the rest of us) went to IRDs and/or Suntours.
So, in short, still looking . . . .