Beach Boys: Wouldn't It Be Nice
When the current theme idea first popped up, it was originally proposed as “under 1 or 2 minutes”. Really tough. 3 minutes is a hard enough limit. Granted, the constraints of AM radio in the 1960s more often than not forced music groups to keep their songs short. Not having been in the business, I would assume the limit had to do with the programming format: my guess would be that the music moguls had a mandate for short songs with time for ads or promos and pertinent sales monologue in between.
That said, many of the top hits were in that range – and those that weren’t were “cropped” such that they did air for about 3 minutes: if the song went on too long, the DJ would cut in before the song was over: fade out with DJ voice-over. Occasionally brutally crimping the enjoyment of the music. But that was the standard.
So… it should be relatively easy to go back in time to most any top of the pops hit from the early/mid-60s, and make a choice for a < 3 song. Sure enough: BBC’s Top of the Pops list from 1965 shows that most hits are less than 3 minutes. “Hang on Sloopy” is near the max length at 3 minutes 53 seconds. The rest of the pack times in under 3.
Considering that there were folks like Bob Dylan, who most likely felt they had something to say and could most probably have rambled on beyond 3 minutes if given the chance, you have to assume there were external pressures along the lines I suggest above.
On the other hand, I also question how many minutes I would have been willing to listen to variations on lyrics such as “Wild thing, you make my heart sing ….” (’66) in a rather limited I-IV-V chord progression.
The short song format worked for a decade or more. It wasn’t until the ‘70s that radio play began to move beyond the 3 minute limit, and part of the credit there goes to “progressive” radio, more often than not in the FM bandwith. I realize this is an over-simplification of many of the influences and elements, but many of the facts remain.
So, here’s one from that era that fits the thematic limits of less than 3. I can't help but think of what a huge job it must have been to (try to) sync the tape vocals to the final film output!