This is what I have done with very old or even unknown films. Load seven rolls with about 5 or 6 exposures plus leader. Pick five test subjects and shoot all rolls the same (all frame 1 on subject 1, 2 on 2.....) at ISO 400. so you have 7 identical rolls. develop in D-76 or ID-11 at 68f for 5, 7, 9, 11, 13, 15 and 18 min. pick the best time and do the test again with three rolls shot at ISO 400, 200, 100. this will give a good idea of yout best time/ISO combination. Then check other charts for films in that ISO that develop near that time in D-76 and check out what other developer/time they use. 35 year old film may still be good but the ISO should be slower and development might not be the same as it was. Good luck