It's hard to answer your question based on the information provided. Will you be using the film for its original purpose--copying old black and white photos? Duplicating films vary in their spectral sensitivity and often react quite differently to different developers. Kodak Commercial, my favorite for copying, is sensitive primarily to blue, and I usually rate it at about E.I. 8 under photofloods, processed in HC-110B for 2-3 minutes depending on the contrast present in the original and/or the final result desired. The daylight E. I., however, is 50; I've never tried it as a pictorial film, but I imagine that the results would have an old-time rendition similar to the emulsions used back in the 19th century. Another film, Kodak Ortho Copy, which I believe was available in 70mm, has a rating of 12 for tungsten and 25 for both White-Arc Flame or Pulsed-Xenon. If you can identify the particular type of film you have, I'll bet that someone out there in APUGland can provide specific exposure and development data.
Otherwise, you'll just have to do a little experimenting, but, hey, that can be interesting too.