If you let him have a free shot I'd say 7.5 but in boxing he still needs to work on his timing, range, accuracy, setting the shot up, walking the guy onto the punch etc Power is one thing but power in practice is another.
There's hardly any punchers in British boxing anymore. Our two best fighters, Froch and Khan don't knock out world class fighters.
6 is about right I think, but that's like 'raw power.' Raw power doesn't necesarily translate to heaps of knockouts.
7 he has decent power, Cleverly is open but one shot wont be enough. "Once your hit your gonna stay hit!" as Bellew says.
Bellew has decent power? Does he fcuk. He's a 4, at the absolute outside best. He's not as powerful as Clerverly - fact. His chin ain't as good as Cleverly's - fact. He'll be suppin his dinner through a straw for a week after Cleverly's finished with him.