Tunney had only six fewer knockouts than Dempsey, and Tunney was a boxer, not a slugger like Dempsey who youd expect to ko people. Obviously Tunney was a very hard puncher, more power than most give him credit for.
It was better than people think it was. Tunney had hand problems early in his career, and when they were sorted out he became prety destructive. Interestingly some of the media saw him as more of a boxer puncher than a cutie, before he fought Dempsey.
He had a good right, left hook not so much. Power wise is pretty hard to judge, his best stoppage is probably Gibbons and that was late, so I wonder if it was accumulation, his second best probably Carpentier or Heeney, both again late stoppages. The rest of the quality opposition he didn't stop So not a knock out puncher really but plenty to get an opponents respect
Tunney had an excellant left hook. If you read accounts of his fights,especially early on when his right hand was busted up, his left hook was the damaging blow. He was also a very very good body puncher. Watch the Gibbons and Carpentier fight, and, early on against Dempsey he lands some ripping hooks to the body. A very hard puncher, in my estimation.
For whatever its worth, Tunney was prety close to stopping Dempsey in both their fights. I think Dempsey counted himself lucky to be spared the indignity of a knockout both times.