I have not found my old book of tables for the scale factor and such from clark 1866 ellipsoid. I can get the scale factor I believe from ngs documentation. I do have a question if someone remembers or can tell me if i am remembering correctly. At Meads Ranch where NAD27 was placed wasn’t the ellipsoid at 0 zero here between MSL and clark 1866 . I was trying to remember the maximum distance between elevation and ellipsoid max separation in CONUS. I believe the error was minimum for it as clark 1866 fit North America very well. So at meads it was ellipsoid and THE geoid were the same. Just all of the numbers blasting through my head since working in this datum recently. Man how far we have come. But some of this stuff is all foggy but somehow got to bouncing around in my head these last few days.