On the night he almost beat Rosario, I think Davis would be very tough for Marquez. But I also cant help but think he'd choke.... as usual.
like X said, Davis found a way to lose every big fight he had, he was a really, really good fighter who just could not win a major fight, a trend I don't see any reason to go against here, even though I think he'd give Marquez hell, like he did basically all of the other guys he lost to... hard to believe in retrospect, but Davis was the man considered most likely to achieve pro greatness out of the fine 1976 crop