Cmonnn, Campbell isn't even worth mentioning. Mancini isn't that bum Juan Diaz... he definitely beats Campbell. The rest are interesting. Casamayor was already past his prime at 135. At his very best, I think he could outclass Mancini, but the older, slower lightweight version would get outworked by Ray. That leaves Castillo and Corrales. Castillo-Mancini is basically 50-50 IMO, but if forced to choose, I'd give a small edge to Ray. That leaves Corrales... I think Chico stops Mancini late in an unbelievable war. Mancini would give Corrales Hell, but in the end, I think Corrales' devastating, precision power shots would take their toll on Boom Boom. Corrales TKO 11.
Very bad example considering A. Corrales was totally washed up in the Clottey fight and B. That fight was at welterweight, and Clottey was a much bigger man than Mancini. Clottey was no scrub. He's totally forgotten now, but in reality, he beat Cotto and got robbed. He also ran Margarito extremely close.
It looks like I'm going to be the dissenting voice here. Although every else seems to believe that Mancini was head and shoulders above Cambell and on par with the others, I believe Casamayor, Castillo, and Corrales were above Mancini's level and Campell and Mancini were roughly on par. Campbell's record is littered with bad losses, but he had a few performances that indicate to me that he could have been competitive with Mancini. Does anyone remember his victory over Kid Diamond, where he deflowered the unbeaten Kyrgstani slugger? He also had a great effort against Ricky Quiles and of course the title win over Diaz. That guy was at least as good as Livingston Bramble in my opinion. As far as the other 3 C's: in my judgement they all have a far better claim to the IBHOF than Boom Boom. Nothing against Ray, who deserves a lot of respect.