Holding amps steady???

Seems like most every Dodge I have had, 1978 and older, does not hold a steady level on the ammeter gauge. I was pondering several things and was wondering if anyone has come up with some good solutions. I know the gauge itself seems to be a week spot on these old Dodges. My 1978 Ramcharger drops down considerably when I have say the defrost, lights and wipers on at the same time. The lights get dimmer and wipers slow down. Most all of the dodges I have had from the 70's and older have done this. Can this be improved with a heavy duty alternator? What about replacing the ammeter with a voltmeter? I have been told on the Mancini racing forum that you would not want to use a high performance voltage regulator on a stock street application. I have the 'orange box' ignition unit. I have a new battery and cable. I am going to run a good ground from the ground on the motor to the body. Any other recommendations? Thanks.

Kevin