Flush volume of pre-1983 American Standard flushometer bowl?

[htroberts]

What was the design flush volume for a pre-conservation AS toilet? 5GPF? 4.5? Some other volume?

Also, does anyone know the most common models in use at that time? It's commercial, obviously, so elongated bowl and only a spud connection up top, no tank mounting holes.

Almost forgot: I'm looking for info on floor-mounted varieties, not wall-mount.

Thanks