I think he'd hold his own. I'm confident Sam could KO Walcott, Moore, Charles, Johnson etc but I'm also confident that they could out-box him. If he fought a series against them results would probably go back and forth like that. Langford vs Marciano would be fun.
I wouldn't favour him over Moore, Charles, Marciano or Patterson, so he'd have to win in the interims. I'd pick him over Walcott, Maxim, Johnson and Marshall. He'd probably have a great fight with Bivins, one I'd pick Sam to win. He'd probably be in the mix, but I don't think he rises to the top.
As a huge Moore fan, I think that Langford would beat him. He seemed to be a bit more durable and his combination of power and delivery should give Moore huge problems. Langford could also make it inside battle if needed.
For the most part I think boxing moved on past this era. But Langford is a special fighter. He has the rare Tyson like ability to make his shortness an asset but slipping punches on the way in and using deadly bodyweight shifting angles inside in a Tyson like manner If the taller technical boxers can keep him outside they're winning there. Most of these men are better outboxers than what existed in Langford's day. To give Langford some benefit of the doubt, he probably adapts his style to the era, once he trained and boxed in the 50s. He'd probably up his game If these men come inside and Charles and Bivins did like to give up range they play into his hands and he will unload his best shots and potentially knock them out. Marciano v Langford is the most exciting fight with both meeting head on to slug it out. Patterson is probably too quick but obviously could be caught himself
pretty excellent post except I think Sam crushes Floyd as Floyd never boxed but tried to out flurry his opponents. I also like Sam over Rocky.