What if any middle weights or light heavies could beat harry greb?

Good question sir. I have to disagree with your first answerer that many modern middleweights could have beaten Greb. Without the newspaper deceisions of the day, Greb had a record of 105-8-3 with a 15 round decision over Tunney who outweighed him by 10 lbs in their first fight. Greb won 12 of the 15 rounds and if this fight would have been fought in more modern times, it would have been stopped and Greb would have won by TKO! This was a win over a boxing master as Greb overwhelmed him by trickery, speed, stamina, and an ability to throw punches non stop increasing the volume every round. Harry Greb also won an offcial decision over Hall of Fame heavyweight contender Tommy Gibbons who would get a shot at Dempsey's title instead of Greb. Greb also defeated Hall of Famer Tommy Loughran and future light heavweight Champion twice by decision with one draw. He defeated Mickey Walker a true all time great by decision and nearly knocked him out in the process. Of those 8 official losses, at least 1 of the Tunney fights, 2 of the Tiger fights and a loss by DQ to Kid Norfolk were controverial. The man regularly beat light heavyweights and heavyweights like Bill Brennan, Billy Miske, Willie Meehan and he kayo'ed Ed "Gunboat" Smith in 1 round! Not only did he beat these guys, he usually beat them in resounding fashion winning nearly every round in the process. Now counting his unofficial record, it's really hard to understand how anybody in their right mind can think of anyone beating Greb on a regular basis including Robinson, Hagler or Monzon. Can you see any of them beating Tunney or running Dempsey nearly out of the ring being outweighed by 30 lbs? He had a ctotal career record of 260-20-18 and was not knocked out in his last 252 fights! He beat the following fighters: Tommy Gibbons, Mike Gibbons, Gunboat Smith, Billy Miske, Bill Brennan, Tommy Loughran, Kid Norfolk, Mickey Walker, Johnny Wilson, Jeff Smith, Jimmy Slattery, Maxie Rosenbloom, Tiger Flowers, Jack Dillon, George Chip, Jack Blackburn, Battling Levinsky, and the list goes on and on. He bet most of these guys multiple times and usually the fights were not close. Nobody had an answer to his style. Grantland Rice said he was a cross between a wildcat and a hornets nest and Dempsey said he was the fastest fighter he ever seen. He was the ultimate prizefighter and the best ever.