Nice! I have an Adamant Infernape with Iron Fist. It knows Mach Punch and holds a Black Belt. All of these factors together make Mach Punch, usually known to be just a weak priority move, hideously owerpowered - enough to OHKO if its super effective and 2HKO if its neutral. See any choice items/leftovers/life orb here?

And that, my friends, is the power of imagination.