I love watching Foreman especially a young one. old foreman was bigger and had still super heavy strikes but he had even more akwwards punching technique and young Foreman had on top of the weight of his punches really fast hands as well.
George Foreman & Joe Frazier are my favourite boxers of all time - for different reasons. Out of the two - Joe Frazier is at the top of the list for me - people call him a slugger but he was one of the best heavyweights at cutting off the ring, ducking/slipping punches - his whole style was about getting around someone with reach and with the greatest spirit I've ever seen in boxing along with imho the best left hook and maybe right hook.
The younger Foreman was much more explosive than the older Foreman but that said the older Foreman was much wiser/smarter with his approach. The younger Foreman often left himself open quite a lot - but his insane punching power meant that very few were able to exploit that *****. The older Foreman was more aware of the *****.
I think people also overlook the fact that Foreman had an iron chin to go with the insane punching power. A great example of someone taking advantage of the openings Foreman left was Ron Lyle - another great heavyweight but this was a severely psychologically effected Foreman. But we also see his iron chin that saved him along with that monstrous punching power. I mean in 76 fights he was only knocked out once by Ali - which is pretty incredible (he was knocked down in fights but never out cold for the count).
If the younger George had the older George's wisdom/mentality - he may truly have been unbeatable.
It's also insane looking at the weigh he stops people he can seemingly get power everywhere while someone like Tyson for example still has to get proper leverage with tyson you see the effort and explosive power he puts into punches in his movement Foreman seemingly just touches you out of awkward position and it's still enough to hurt you.
Wladimir klitschko tbf someone does the same with his left hook but he has textbook punching form even though his left hook is incredibly short but Foreman does whatever he wants with every pucnh and it works
There's no kink in the leverage chain - that's what I think Foreman's secret is - everything is compact/stable. When he punches it's one whole mass together going into the target - it's something that some people instinctively do better than others.
I think your stability bio-mechanically along with actual technique plays a huge role too. I think very few people focus on strengthening the actual leverage chain from the ground up to the actual fist enough.
I'm of the belief that the forearms, wrist and triceps play an abnormally important part in the delivery of leverage especially with hooks - I feel this is where most of the leverage generated gets eaten up.
I've always had naturally big shoulders/triceps but weak wrists. As soon as I started strengthening my forearms/wrists and toughening up the hand - I felt huge improvements in the leverage I was able to generate - punches felt much more solid/more impact than before. To the degree that I must state again the difference was enough that I've kept up the practice.