I almost never disagree with bundini, but in this case I have to go old school, given Moore's trouble with Durell and Langford's success against Johnson, I like Sam Langford's chances. Two of boxing's historical ultra elite, but I have Langford a slight favorite and Moore the slight underdog.
I'd go with Old Mongoose Archie Moore. He's got better skills and all the tricks of the trade. He'd outsmart and outpunch Langford.
Gotta go with Archie Moore by Close UD on this one, Sam would definitely make it a fight.