The Boston area was fertile ground for Top 40 stations on FM during the early 70’s. There were a number of them experimenting with the format. Experimenting is the right word as these Top 40 stations and others throughout the country featured wider playlists and were more influenced by the FM Free Form and AOR stations than their AM counterparts. Hallelujah by Sweathog and Starman by Bowie are two of the tracks featured and they did not get much AM airplay.
There were also stations playing oldies and a hip version of soft rock with artists such as Jackson Browne and Buffalo Springfield
The clip above features:
WBZ FM ( station ID at 7:48).
WEEI FM ( DJ at 10:11).
I believe one of the automated versions of WROR FM ( DJ at 2:36 and 11:44).
You will also hear a bit of WHDH AM ( ID at 11:54) which had a MOR format and WEZE ( DJ at 12:18).