What size of alternator to use

Need some help figuring out what size amp alternator I need on my 67 GTX. Right now I just have a standard alternator on the car but with my electric water pump, electric fuel pump, dual fans on the radiator and fan on the transmission cooler the two batteries in the trunk aren't staying charged up. Any help would be greatly appreciated.

Here you go.
https://www.forbbodiesonly.com/moparforum/threads/alternator.227938/
I still have it.

I normally run 120A Denso alternators in my cars. Typically I run EFI, 1 or 2 electric fans, decent stereo, etc.

An alt able to feed as must as posible your needs at iddle or close to iddle.

So, you needs to make the maths on how much amps your car will regulary use.

For stock cars, my suggestion is get an alt able to source 45-60 amps at iddle, depending on options and driving conditions on regular use ( AC, rain, traffic, night driving... ). These alts use to point out to alts rated at 80-100 amps as max output ( usually reached at 1800-2200 rpms or so, depending on pulley diameter and alt itself specs of course ), JUST IF REQUIRED, not a constant feed. Remember amperes are not pushed in by the power source, but sucked out by the equipment.

Smaller pulleys helps out on get more juice from alts at iddle for street cars but not so good on race or high rpms cars due heat and bearing stress ( and several other issues )...

With that kind of added accesories, well, begin to sum the load request by every add on, but as mentioned, a 120 amps alt could be pointing out to a pretty decent alt rate to hold that stuff without get worried a lot about the batt discharge stage.

Just make sure you don't get one that's too large to fit.