A lot of guys are replacing their generator with an alternator, this is OK if you have a '56 or later but for those of us who have the original 6 volt system in the older cars and want to stay that way, either for staying 'original' or for wanting the radio and other things like gauges and heater motors to work, there's no reason not to have a good working and reliable generator & regulator setup.
Generators are actually simple, take it apart, clean everything with ether, it's fast but do NOT SMOKE while doing it.  Next is to check the armature, it has to be done on a 'growler', take it to a shop that has one, only takes a couple of minutes to test.  If good you're 90% in the clear.  Next is to check for continuity of the field coils, also test for shorts, you must disconnect the grounded field wire to do that.  Put in new brushes, make sure the brush springs are OK.  Have a new rear bushing put in, also a new ball front bearing.
If the commutator on the armature is smooth and not burned, smooth and clean with fine sandpaper, NOT the black paper used in body work, use fine flint sandpaper.  If it's not true or rough, get it turned, the mica undercut also.  Put it together and you're in business.
As to regulators, there are books that show how to fine tune them, I've found that a decent old one is better than you can buy new, most are not made in the USA anymore, maybe none.   I search junkyards for old originals, then try to tune and fix them.  All Ford 6 volt generators and regulators are 30 amp, more than enough for any car or truck, you do not need excessive amperage.  Don't try to use a GM Delco regulator with a Ford generator ... bad idea.  Plymouth or Dodge regulators will work with Ford but ....
Warren