When Columbia Records sent copies of Simon and Garfunkel’s “Fakin’ It” to radio stations across America in the summer of 1967, the 45s' printed labels would have looked normal to DJs at first glance. It had the song’s title, its writing credit, and all the relevant copyright information. Had they looked closer, however, they would have noticed something funky with the runtime—it’s listed as “2:74,” not “3:14”:

Kent Kotal // Forgotten Hits

At the time, radio stations were wary of playing pop singles that exceeded three minutes. The label trickery on the three-minute, 14-second “Fakin’ It” made it look like the song lasted a brisk two minutes and change, and they banked on the fact that radio DJs weren't the closest readers in the world. (It likely worked—"Fakin' It" reached no. 23 on the Billboard Hot 100 chart.) 

The above photo comes from Kent Kotal’s Forgotten Hits blog, a compendium of ephemera from the golden age of pop radio. “I don't know that there was a written or hard-fast rule about records having to be under three minutes in length,” Kotal tells mental_floss via email, “it was just the accepted practice at the time.”

The “three-minute rule” has its origins in the technology itself. The 10-inch records pressed in the first half of the 20th century could only hold three-to-four minutes of recorded sound. "If it went longer than that, the grooves became too close together ... the sound quality went down," Sony Music archivist Thomas Tierney told Mashable.

Even though the technology improved in the 1940s and '50s, and 45 rpm extended-play "EPs" could handle longer songs, three minutes acted as a barrier for radio airplay well into the 1960s. “Nobody wanted to commit airtime to more than that,” Kotal says. “This way they could still get in all their sponsored ads, the then-typical two newscasts minimum per hour, weather, traffic, sports and even some fun deejay chatter back in the day when jocks were still allowed to talk on the air.”

Simon and Garfunkel weren’t the first artists to cleverly get around the three-minute rule. The Righteous Brothers’ 1964 smash hit “You’ve Lost That Lovin’ Feelin’” lasted a full three minutes and 45 seconds. Producer Phil Spector’s solution? Lie. He stamped “3:05” on the single and called it a day.

"Fakin' It" proved to be one of the last times artists exercised temporal gymnastics to get around the three-minute barrier, as, by 1967, the rule was already on its way out. The next year, Richard Harris’s seven-minute, 21-second “MacArthur Park” hit number one on the Billboard 100—and he didn’t even have to stamp “2:201” on the single's label to get it played.