well how bout the cork-screw punch?

Screwing the punch is very effective and is used regularly by fighters such as Hamed and Hatton.

 

Personally, I think that's mostly urban/ring myth. As an amateur (lightweight up to light middleweight) I often sparred light heavyweights and heavyweights when nobody else was available. It helped them with their footwork too.

But I was definitely the guy who'd hafta be careful. The heavyweights knew they could take me out with little more than a jab, so they'd punch mostly to the body.

One heavyweight in particular, a two-time Texas state Golden Gloves champ, would pop me in the chest with jabs and right hands. He'd literally move me backward and it felt like my sternum was being introduced to my spine.

But I never felt stunned. Damned impressed, sure, if you mean psychologically stunned. But I didn't feel like my ticker was gonna stop.

I think what happens is that occasionally a hard shot to the upper chest knocks a guy off balance. That's how Wepner floored Ali. He sure as hell didn't hurt Ali, just knocked him off balance when Ali didn't have his feet under him. (BTW, I give Wepner credit for the knockdown - I just don't think it was a big deal.)

Now, an inch or two lower and the Fitz solar plexus punch will definitely put a hurtin' on ya.