Bruce Lee, with a 6 inch punch he lifted a heavyweight flying off his feet about 10 feet. Look it up on YouTube.
There was a heavyweight in the 80s that had a big jab. Pinklon Thomas. It was Liston's like. Hearns had the hardest in the Middleweight divisions. Lower weights Azumah Nelson.
If we're talking p4p power then I'd put forward my man Golovkin's jab at MW for sheer impact. He's scored KD's with his jab before.
There was a guy who used to post here (MagnaNasakki) who sparred them all and gave it to Wlad. Went into great detail about the effect of it. Probably one of the most interesting posts I’ve ever read.
Come to think of it, I’m not sure if he was exclusively talking about the jab or just overall power, but it was a great read regardless. Gonna see if I can find it.
Liston Foreman Quartey GGG All had superb power jabs From what I remember reading Gans would would mix up his jabs with a very hard dropping step strait left designed to really hurt. Hagler also had a very strong jab when he stepped into it with the right hand.
I think he had a great jab. It was very powerful and quick. He outjabbed Hill and alot of other despite having a shorter reach.
Liston's was strongest, but Foreman was right up there (not as fast, and not quite as stepped-into). Obviously a difference between strong and best. Holmes to me had a terrific jab, and perfect for heavyweight. Fast, heavy, viciously twisting. Hearns had a great one. Both Tyson and Foreman would have won a LOT more fights had they relied more on their jabs. Joe Louis had a fine jab, got better as he kept fighting.