I have a mabuchi 555 motor. The full load torque is 380 g-cm. The stall torque is 1,360 g-cm. Does this mean max torque is 1,360 g-cm?

 

NO !!!

If the Motor is operated at more than 380 g/cm,
the Motor will eventually start to OVERHEAT,
and is very likely to fail.

"Stall-Torque" is the amount of Torque generated when the Rotor is completely STOPPED.
This is more commonly referred to as "Locked-Rotor", and is not a very useful number unless
the Motor will have to get a very-Heavy-Inertia-Load up-to-speed,
and therefore,
the Motor may spend a significant amount of time in a hazardous, over-loaded, condition.

To avoid these conditions, it is a good idea to use an Electronic-Motor-Controller
which can control, and/or, limit, the Current being supplied to the Motor.

A more useful specification-number is "Locked-Rotor-Amps",
which is how much Current the Motor will demand at "Stall" speed.
This number is good to know when designing an Electronic-Controller for the Motor
which must be able to withstand the "Maximum-Locked-Rotor-Amps".
.
.
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The stall CURRENT is also the current spike that flows at the instant the switch closes, if the supply voltage does not drop a bit.