NYC FM processing in the mid to late 70's was obviously intended to be loud and dense. While I was doing due diligence on WTFM in '79, I noted how clipped everything was on the contemporary stations, and theorized that most also had Eric Small's composite clipper set to 2db or 3db. I found it most annoying, but this was likely the "hangover" from AM loudness wars that we all experienced, right down to the Audimax with the 0-ohm resistor.
David, if you arrived here (NYC) in 1979 you were spared the worst of the asinine loudness wars. The AM's WABC and WNBC had adopted the dull-thud school of multiband a few years earlier and the only screamers on FM were WPLJ -slightly refined from that aircheck and WYNY (Hot-AC) -which although heavily compressed was also clean and well defined. WPLJ processing went more mainstream in mid-1984.
The loudness wars were pretty-much in remission till Z-100 and it's brutal use of clipping. Although that chain allowed greater apparent strength of bass, the end result in most receivers was mush and IM distortion. I never understood the praise that air got back then. When Scott Shannon went to 'PLJ around 1990 that mush followed him.
The use of comp-clippers AKA: "pilot stompers" is actually as bad today as it was 25 years ago. It is not at all unusual to see the indicator go out on heavy bass transients.
LCG