Cervantes. Arguello was still excellent in early days at 140, but I don't think he'd get very far with a beast like Cervantes. I'd take Kid Pambele to win either a clear decision over Arguello, or stop him late. Arguello's level at 140 is around that of Tzysu or Hatton IMO. I'd take him over both of those guys, there.
Funnily enough, this was done only the other day on ESB. I think this is a closer fight than some have it but I take Cervantes on points. Would have been a high quality fight all the way, though.