As i read from old TI catalog, if the the low output sink current is max.24mA, the saturation voltage max. 0.5V (typ.0.35V). The high level out.current only max.2.6mA.(because in LS serie the high-side driver transistor have 100ohm resistor seriel with collector)
The fan-out=20 inside the familyne output can drive up to 20 inputs.