Bad matchup for Shavers. A guy with bad stamina and not great whiskers. Yeah he could punch but Marciano was a lot more elusive than given credit for, particularly when he was on the offensive and he wouldnt have to look for Shavers. I think he eventually stop Shavers.
Shavers would be a dangerous opponent for Marciano, but the smart money would be on Marciano's consistency, over Shavers chin.