This was a long time ago, back when Steak & Shake had multiple shake sizes; small, medium, and large. At some point they moved to only one size; 16 fl. oz.
In those days, a large shake was 32 fl. oz, or a quart. The most I had at once was two of them. I was rail skinny back then, so I had to eat almost nothing before doing that. Oddly enough, I haven't been able to repeat this or something similar.
At some point, I may try to melt a carton (most are 1.5L or 48 fl. oz) and funnel it. As the whipping effect and thus, volume is lost, that should condense to about 32 fl. oz. - 1 quart.
It might be easier than the heavy cream + nutritional shake 50/50 mixes I often like.
4 years