This will no doubt show my age, but I was in high school from '83-'87, so hopefully I'm in the range you're looking for.
For me high school consisted of two days, "A Day" and "B Day". Each one had four classes that were an hour and half long. We called them first period, second period, etc. (The B day was fifth period, sixth period...) We had a mini-break of roughly five minutes between classes to get to our lockers (and/or bathroom) and then the next class. Lunch came in the middle of the day.
I'm wracking my brain trying to remember how lunch worked because you either had first lunch or second lunch, each of them were 45 minutes long. We didn't have study hall or anything like that so I can only surmise that which lunch I had depended on when my third period class started. I think half of them picked up right after second period and the other half had the 45 minute break before starting.
Hope that helps.
