bypass video

Your alternator has probably been changed a couple times in the last 50 years. Original alternators were 34 to 56 amps. A lot of the ones you get today are 60 to 100 amps and now run it through 50 year old wires and connectors that have never been cleaned (see above).

I am a big fan of ammeters. They tell you a lot about what is going on electrically in your car. A volt meter is like an oil pressure idiot light - it tells you that you are screwed after you're already screwed. You can see things failing on an ammeter that will never show up on a voltmeter. The original ammeters were never meant to last 50 years (5 years or 50,000 miles whichever comes first, right?). My favorite way to avoid disaster is:
1) replace the original wiring with an in kind replacement (M&H is my source) underhood and dash
2) if you find the need to install a bunch of add on stuff that uses electrical power, do what Chrysler did for cab and cop cars - replace the 2 main wires in the bulkhead connectors with larger gauge wires and drill and grommet holes for them eliminating the bulkhead connection for these to wires. Run new fused wires for the new stuff (don't add their load to original well designed circuits).
3) leave the original ammeter in the dash for looks (not hooked up) and install an aftermarket ammeter under the dash along with a voltmeter (and while you are at it a mechanical oil pressure gauge)

Now you have a much better idea of what is going on under your hood while driving, and don't have to worry about a catastrophic fire for another 50 years. Yeah, I know this ain't cheap, now add up the cost of everything you have done to get your car and everything you've spent on it since and think about it all burning up on the side of the road...