Steroids do waaay less for strength than they do for muscle hypertrophy...
You're a funny guy.
So putting one hundred or more pounds on one of the major lifts within several months isn't too dramatic, right?
Also, Casey was using, 100 percent. Not that this is some big deal.
Fact is, he pressed a poundage many decades ago that still only a handful of folks today can do. I have no doubt he didn't pause the rep and I have little doubt he did, in fact, have an arch of some sort, as this is only prudent and wise (arching the back is paramount to maintain shoulder integrity and properly mechanically "set" the upper body, after all), but still,
what a number.
Oh, one other thing. Physical strength and durability is, in a natural world, a more valuable commodity than is a ripped and sinewy body.
Hope
this helps.