WSPK

In 1979, Stew Schantz (who also had worked stints at WPDH, later WSPK program director) re-worked the station's image, branding it "K-104". Schantz and the station's sales manager, Chuck Stewart, picked up the idea from a sales conference out west (there, station call signs usually begin with a "K" where east of the Mississippi River they usually begin with a "W"). The new name worked wonders for a station which had spent the previous decade adrift. Stew returned to mornings at WPDH, but he would later return again to K-104 in the late 1980s. Jim Simonetti was WSPK's first PD in its new incarnation as an Adult Top 40 calling itself K-104. He would later transfer to Beacon Broadcasting's WSCR in Scranton, Pennsylvania. Chris Leide would succeed him as PD until 1989, when afternoon host Sean Phillips would become PD until 1992. Mark Bolger, currently at WCZX (MIX 97FM), joined K104. As a later evening DJ, Bolger was nicknamed as "The Bolge" from 1985 to 1988. He then handled the K-104 morning drive as "Mark Bolger in the Morning on K104" until 1996. Mark Bolger's "Record Crusher" segment, a test play on new hit records, was a notable trademark of his evening show. Nick Robbins also rocked the Hudson valley in K104s early Rock of the Hudson Days, Stew Schantz re-joined K-104 in 1988 after leaving the "Stew and John Morning Show" at WPDH, initially handling the afternoon drive before eventually moving into the midday slot. The "All-Request Lunch at Noon with Stew Schantz" also debuted, with Scotty Mac as the current host as the "All-Request Lunch at Noon with Scotty Mac". Scotty joined the station in 1989 originally handling voiceover and commercial production work with weekend host (and later MD) Chris St. James. With the exception of one year being at KHITS Tulsa, OK in 1998, Scotty Mac is the longest tenured air personality at the station, and is currently midday host and PD.

By the early 1990s, K-104 evolved to a more adult-leaning approach as the CHR format went into a short-term decline. The decline was mainly due to country music's resurgence immediately following the Persian Gulf War. With this, the numbers weakened even though there was no real competition for its target audience. In 1996, owner Beacon Broadcasting sold their remaining stations Enterprise Media of Binghamton. Under this new ownership, Mark Bolger left the station, and Stew Schantz handled the K-104 morning drive. Their ownership was short lived, as they in turn sold WBNR and WSPK to Pamal Broadcasting in 1998. Upon Pamal's take over, Schantz resigned from the station. He later went on to do behind-the-scenes work in Utica, Albany and Pittsfield, Massachusetts. Schantz died in June, 2010. The sale to Pamal ended K-104's running of weekend shows such as Open House Party with John Garabedian, Classic Dance Tracks with Stevie T, as well as the K-104 Hometown Countdown.

After Schantz's departure, Brian Krysz took on the program director's responsibilities and hired Kent Bonham ("Woodman") to handle the K-104 morning drive. Krysz programmed the station until May 1999, when Scotty Mac (formerly nights in 1991) took over. The changes led to a re-imaged CHR approach which leaned towards dance music. The station's ratings improved, regaining top position in many key demographics, as well as the 12+ bragging rights. Though in recent years weak competition has come in the form of WPKF and the station is a perennial #1, K-104 is still a dominant force in the Hudson Valley radio markets. K-104 also has the distinction as being the oldest FM 24/7 top 40 station in continuous operation in the United States, as this station pioneered such format on the FM radio dial. Other radio stations in the country including WPLJ, WHTZ (Z-100), KISS 108 (WXKS-FM) Boston and KIIS-FM Los Angeles, would later evolve and emulate into similar 24/7 radio formats. The late Stew Schantz is considered a pioneer in establishing this type of radio format, as he is listed as one of the notable program directors and disk jockeys in the Rock and Roll Hall of Fame (alongside Alan Freed, Dick Clark, Casey Kasem and many others, local and national). Jarrett "Skywalker" Galeno joined K-104 in 2000, from WBLI-FM. Holding down assistant program director responsibilities, he also hosts afternoon drive.

Kent "Woodman" Bonham originally hosted the K-104 morning show from 1998 to 2006. Upon his exit, Chris Marino took the helm from 2006 until 2009 when Kent "Woodman" Bonham returned. Woodman has continued to host mornings ever since. The current morning line-up features co-host Jill, long-time morning news voice and K-104 personality, Bill Beale, and a diverse cast of characters.

K-104 is known for its use of voice-over veteran Mark Driscoll as the station's voice from 1994 to the end of 1997 and from 1999 through today. Before Driscoll the legendary Mitch Craig was the voice guy.

K-104 is the Top 40 radio station in the United States whose terrestrial radio is broadcast over more states than any other Top 40 station in the country and currently can be heard in New York, New Jersey, Connecticut, Massachusetts, Pennsylvania, and Vermont.

In early 2003, Pamal Broadcasting purchased WYNY (107.1 MHz), the Westchester County portion of the "Y-107/Rhumba 107.1" "quadcast" from Nassau Broadcasting (which itself had bought all four stations from Big City Radio). On April 9 of that year, WYNY took on the WXPK calls and the stations relaunched as "K-104 and K-107". Due to various problems keeping the station on the air and generating revenue with the Westchester signal, the simulcast ended one year later when the 107.1 frequency changed to adult album alternative as "107.1 The Peak".