That may not be an earth-shaking headline. But considering that they also led the league in OPS+ and DER (defensive efficiency rating), that is impressive. Probably not a big surprise since they are often seen as the greatest team ever. I wrote a post a few weeks ago called What You Don't Know About The 1927 Yankees. It discussed some of their statistical accomplishments. Their won-lost record of 110-44 actually understates how good they were.
The table below shows how the teams ranked in FIP ERA.
FIP ERA = Constant + 1.44*HR + .33*BB - .22*K (in this case HRs, BBs, and Ks are per 9 IP). The constant = League ERA - (1.44*HR + .33*BB - .22*K). The idea is to see how good pitchers are based on the outcomes they control. I think it was created by Tom Tango and is a little like DIPS ERA created by Voros McCracken.
DER is percentage of batted balls turned into outs. See the first post linked above.
OPS+ is 100*[OBP/lg OBP + SLG/lg SLG - 1]. It is then adjusted for park affects. The 1927 Yankees led the league with 128. The next highest team had 99. To see the stats for that year, go to this Baseball Reference link: 1927 AL Team Hitting Stats.
There probably are not many teams that lead the league in FIP ERA, DER and OPS+. If I find any more, I will report it. It means they had the best pitching, fielding and hitting. Some combination.