On July 15, 1980 In an 11 – 7 Cincinnati Reds win over the Montreal Expos, Johnny Bench belts homer #314, establishing a new mark for home runs by a catcher, and #347 overall. The round tripper comes off David Palmer. Bench breaks Yogi Berra’s record and will hold the mark until surpassed by Mike Piazza.

Source
Baseball Reference July 15