Re: Who tested Marciano's chin?
ChrisPontius has it for me...only down twice, both of those very briefly, without any lingering after-effects, and taking many many punches otherwise without even stumbling.
The hypotheticals about how he'd do against a puncher like a Foreman or Tyson have to remina just that, hypotheticals. In terms of what Marciano was able to do at the time, he clearly had some real rock in that chin and I judge him on that.
Now, TKOing Marciano due to facial damage...that could be possible.
Knocking him out cold, I severely doubt anyone does that.