Prime for prime Valdez wins this by Ko, too powerful, hard hitting and rugged for Hearns to handle over fifteen rounds.
I'm not all that familiar with Valdez but he's probably too strong and powerful for Tommy at 160. It's likely to be a stoppage win for Valdez but you can never rule out a Hearns KO against almost anyone.
I'd bet money on Hearns not being able to knock Valdez out, mainly because the latter was (aside from being durable) too strong and powerful and would have Hearns backing up. Good fight, interesting... It might just be that Valdez loses on points, but there's just as equal a chance of him scoring a knockout if Hearns gets a bit too macho. Valdez was a great hitter.