rear dropout width measured inside is 127/8mm and it's built for 27s. Not sure whether it would have been 5 or 6spd in 1970
126mm OLN = 6-speed
If you want something that looks like a mid-range 1970 bike, you should be thinking about now-defunct European brands. Maillard hubs, Simplex or Huret gears, Atax bars and stem, Nervar cranks. If you want something that will be a pleasure to ride, just stick 2011 Veloce on it like a sensible chap.
126mm OLN = 6-speed
If you want something that looks like a mid-range 1970 bike, you should be thinking about now-defunct European brands. Maillard hubs, Simplex or Huret gears, Atax bars and stem, Nervar cranks. If you want something that will be a pleasure to ride, just stick 2011 Veloce on it like a sensible chap.