I think the original 1952/53 gauge was an ammeter, not a voltmeter.

http://www.classicparts.com/1949-53-Battery-Gauge-w_-White-Needle/productinfo/24-701B/#.VVY5zRdHf48

Maybe Jerry or someone else will comment on using a "shunt" with an 80 amp 12v alternator.

I have run a 60 amp 12 alternator with no problems.