Rob,
I'm not familiar enough with the 727 to say with certainty. Nonetheless, my gut feel is that the load would not be near that. Small single pointer engine gauges are generally simply a synchro receiver with a point on its shaft. One of these is a few watts. Larger instruments with with motors servoed to synchro signals (e.g. ADI) are on the order of 20~30 watts.
Mike