I applied in the mid- 1970's. Overall, the process was the same. Back then, the overall acceptance rate was about the same as it is today, around 43%, if I remember correctly. The year I applied application numbers peaked, and I believe acceptance rates got a bit higher the following years. Individual school acceptance rates were about the same as well.
The GPA you needed back then was essentially the same as you need now.
The MCAT back then had four parts: Verbal, Math, General Knowledge, and Science. Each was scored out of 800, like the SAT. You also got a percentile score for each part, but there was no combined score. It was a paper exam, and you filled in the bubbles with a #2 pencil. Lest you think that this is archaic, please note that the LSAT exam ( for law school) is still on paper. I think it took 4-6 weeks to get the scores back.
Based on my experience then with the application process, after converting my old MCAT scores to the current ones ( by utilizing the equivalent percentile scores, and counting the verbal once and the science twice ) it seems to me that the MCAT score percentile requirements have not changed either.
Everyone I knew took a review course for the MCAT, although preparing for the SAT was almost unheard of then, at least among my classmates. I believe Kaplan was the only review course for the MCAT around at the time. I eventually taught the MCAT for Kaplan at the company headquarters in Brooklyn, where Mr. Kaplan himself was always around, still running the company. For those of you who aren't aware of this, Stanley Kaplan single-handedly founded the test prep industry, and eventually forced the test-makers to acknowledge that students could prepare for the exams and improve their scores by studying, something that the test companies had steadfastly denied was possible, until Stanley Kaplan came along.
The AMCAS application was similar, but I don't recall 15 the separate spaces for activities. I typed out the application and mailed it in, and AMCAS photocopied and mailed out copies to each school. Secondaries were similar, I believe, but all hand typed; no cutting and pasting. One advantage to that was that applicants were less likely to put in the wrong school name.
The personal statement was important, and the interview process was important as well. The interview process and interview questions were the same as they are now, although there was no MMI yet. I didn't have any stress interviews.
What was different was that the ancillary activities that are de rigeuer today, such as shadowing, clinical experience, volunteering, and research were not as necessary as they are today. I did none of them, although that probably hurt my application. Some of my classmates did some or all of those activities.
When I applied, the question was " have you had any clinical experience" rather than " what clincial experience have you had" .
One other thing that has changed is that the USMLE step 1 exam score is now very important for residency applications. That phenomenon seems to be about 10 years old. No one that I work with who finished residency 10 years ago or more has any idea what their step 1 score was. We were just told that we had to pass. Now, that score seems to determine whether you have any chance at getting into a competitive residency. By the way, when I took that exam, it was known as the NMB parts 1, 2, and 3. ( NMB= National Medical Boards ) .