Mike, most of the pine floors that I have seen in the old homes of the northern (midwestern) and northeast homes have been of either old-growth knotty pine or heart-pine. The latter is a much harder pine and more resilient to nicks, gouges, scuffing, marring, etc.
Unless I miss my guess, heart-pine is what you are looking for?! Heart-pine finishes beautifully and looks beautiful on the floor.
Another choice is pumpkin-pine, but it has a more orangey tone to it then knotty or heart-pine. Not sure if that would work for you....color wise?
Just a little FYI. :Thumbs:
