I haven't had my hands on that kit in many years (unfortunately; it's an excellent one). The figure 1/160 is also the one in Dr. Graham's book, Remembering Revell Model Kits. I think that may be on the small side, but there's no way it's as big as 1/100. I think it's in the vicinity of 3/32" = 1', which is 1/128.
To get a real answer you need to get hold of a set of plans of the actual ship, and compare some measurements. Plans of the Morgan appear in several places. There's a fairly comprehensive set in the book Mystic Seaport Watercraft, and I believe John Leavitt's book, The Charles W. Morgan, contains at least a couple of basic ones. Taubman Plan Service (www.taubmansonline.com) also sells a full set, if you're interested.
The kit is one of my favorites - one of the best plastic sailing ship kits ever. My one substantive criticism of it concerns the way Revell handled the whaleboats. The hulls are beautiful, but (if I remember correctly after all these years) only two of them have interiors. The others are supposed to get vac-form "covers" - utterly un-prototypical for a whaleboat. (There's no way a whaleboat, with its mast, etc. sticking out, could get a cover like that. And the boats were kept ready to hoist out at all times when the ship was on the whaling grounds.) Another point to watch: in its initial release, at least, the instructions advised the modeler to paint the hull with the "fake gunport" scheme. Generations of visitors to Mystic Seaport came to think of the Morgan as looking like that, and that's how she was painted when the kit was originally released. Since then, the research staff at Mystic has established that she never had that color scheme when she was in active service. (Lots of other whalers did; the Morgan apparently got "port-painted" when she was being used for the filming of a movie in the 1920s.) She now has an overall black hull - maybe not as attractive, but more authentic - and far easier on the modeler.
Good luck.
Youth, talent, hard work, and enthusiasm are no match for old age and treachery.