It's not a strong line of argument, but some common opponents said that Liston hit harder than Foreman, and at least one common opponent said that Foreman hit harder than Lewis. A bit of he said she said going on there of course, but you might take it to mean that at worst, Lewis didn't hit massively harder than Liston.
Liston never hit harder than foreman definitely not tbh most people mean that he was as good as george foreman in terms of boxing but as hard? Definitely not. Was a hard puncher but not in that territory
People forget to realise that the average heavyweight in the 60's weighed around 195, and in the 90' and 00's was between 227-230
They used to call him Sonny "Flintstone'' because he had the power of a stone-aged cave man and was born from then.
There were common opponents/sparring partners who said that the hit harder. We have to take their testimony seriously, in as much as we are ever going to take such testimony seriously.
I'm pretty confident in saying Lewis had a substantially bigger charge of explosives in his gloves than Liston.
No, most people here remember this, it's well known. But how heavy your opponents are has literally nothing to do with how hard you punch. There is absolutely no connection. It is utterly irrelevant. It does create an imbalance in evidence, but all this means is that this isn't suitable evidence for drawing conclusions. Which a subset of people rush to do anyway. It is strange.