My batteries keep dying and won't recharge!

Another view:
50-60-70-80 years have not been kind to our old truck fuel systems. You have to ASSUME the "soda straw" that begins at the inlet of the fuel pump and goes to the bottom of the gas tank has at least one pinhole in it (probably several). It only takes one pinhole to cause you to walk home. CB has a general disposition against messing with stock systems but time takes a toll on everything. An electric fuel pump will push fuel to your empty carb bowl without cranking the engine over and killing the battery.
Get a good one and mount it as close to the tank as possible. But please replace all the fuel lines.
I spent a month or more cleaning out and repairing the holes in my D-2 gas tank. It was a mess! You can't go by the overall condition of the truck, my D-2 is in great shape, overall. My point is that your gas tank probably needs attention, too.
Electric fuel pumps and mechanical fuel pumps will live together if you have seperation anxiety.
I've been heckled on this site about electric fuel pumps in old vehicles but if you ever watch Chasing Classic Cars on TV you know that major classic cars like Pierce Arrows, Duesenbergs, Packards often have a later added electric fuel pump and fuel cell. If aftermarket electric fuel pumps are trusted in historic $3,000,000 cars then aftermarket electric fuel pumps should be fine in our old $1250 Internationals.

MM, remember that this guy is a 15 year old kid, doesn't have a lot of money to throw at it. dollar for dollar replacing the fuel line is a good bet, I'd start there. A pin hole in a fuel line will not necessarily show any outward sign of a hole, fuel will evaporate and show little or no staining. a $100 fuel pump is likely not in the cards.

CB, I was a 15 year old kid with a cantankerous old pickup once, too! I think I had more disposable income to throw at old trucks, then!
No bills, living at home, no children...
I agree that doing the cheap things first is the way to go.
I'm sorry to swim upstream but in his case I'd have a 12v battery, 12v alternator and "solenoid" fuel pump, new fuel lines in it within the first week. THAT'S the cheapest route. Install 12v bulbs, add a 12V coil w/ballast, swap polarity to match 12v negative ground and disconnect gauges and accessories until more money showed up. Starter will live.
That alternator would keep the battery at top charge and that cheap fuel pump would reduce the extended cranking.
If I recall correctly the generator pulley goes right on the alternator for the fatter belt and the new alternator bracket can be built in a pair of vise grips.
The 12V system by design causes much lower voltage drops at any bad connections (a Godsend) and increases chances of starting. Starting is GOOD.

We're never going to see eye to eye on that. One thing tho, by finding out what's wrong and fixing it, he is going to learn a bit.
While a genny pulley will fit on an alternator, it turns it too slow, low output at idle (abit better then a genny) and higher cut in speeds if one wire is used.
You'll never get me to think these trucks sat around until 12 volt was "invented".

Boys...boys...boys.

The advice on the battery cables is spot-on. But with a 15-year old, when you tell him to ground to the starter case, it might be best to advise grounding to one of the starter mounting bolts.

The fuel line advice is good advice. My dad had a '79 Plymouth Volare, and he "killed" 3 fuel pump diaphragm before he found the spot where the fuel line was rusted where it passes a crossmember.. it would still flow fuel, but it would also suck up rust shards that would puncture the diaphragm in the pump. And from what was visible, the fuel line LOOKED fine. That was 25 years ago, and that Volare was 25 years newer than the Binder in question.

Remember, they wouldn't say the scatological equivalent of "manure occurs" if it didn't.

But I agree: fix the current draw/ charging flaws first, THEN talk about going to 12V. The cloth insulation on the original wires rots, and then the natural rubber deteriorates. Better to fix that kind of stuff first, and then move onward.

Buzzman, I'm pretty much a 15 year old boy all the time when it comes to old trucks. I guarantee you that 90% of the bucks-down folks who obtain an antique pickup DON'T go looking for an expensive, scarce and weird 6V battery. They throw caution to the wind and toss in a cheap, used, good 12V battery. If THAT battery is no good they find another 12V battery. 12V batteries are everywhere! The "12V vs. 6V controversy" is not a controversy at all when you have no money. 12V rules the day, everyday.
Since expediency and cost are determining most things and NOT the Old IHC Forum, the next item on the agenda is to install a cheap reman or used GM alternator. Not only do they work well they fit right on most engines with a quick bracket mod, they also render unneccesary about 10 feet of old wiring harness to the remote regulator. Just another in a long series of plusses for 12V conversion!
Yes, old cloth-covered wiring IS scary. It should ALL be replaced. But when you are bucks-down you just bypass what you have to. We might not agree HERE but the world does not care!
I like using the seven-wire trailer harness that you buy by the foot. It's heavier gauge wire and high quality. You can wire most if not all you need to with 50' of it? It sure speeds things up. Not stock, but bucks-down people can't worry about that.
If you haven't noticed yet the "I can't get fuel to my carb" thing is epidemic in old carbureted vehicles. It's to the point where diagnosis is useless because the complainer doesn't even own or understand a vacuum/pressure gauge. It's my firm belief that just about everything old and carbureted that you intend to DRIVE needs to be converted to rear-mounted electric fuel pump along with new metal and alcohol-resistant rubber fuel lines. Don't pull hair out, just CONVERT. The rear-mounted electric fuel pump/fuel line replacement is the BEST thing for our antique trucks.
We spend so much time in our lives pussy-footing around each other, the above statement is the TRUTH.
If these stupid arguments continue I will leave. No one listens to what you say here, anyway. I really have better things to do!

Monsonmotors, If the "pickup" line in the tank is bad, your electric fuel pump will do no good until that issue is fixed Oh, and If you want to get in a snit and leave for good or for a while, That would be your choice. The only folks NOT welcome on the forum are spammers. We have only removed ONE person in the years that I have been on this forum. If you think "no one" listens and read what you post, YOU are wrong, many read "Both" sides of the "argument". You have years of experience and knowledge, and are an awesome "fabricator" in using old sheet metal on Newer power trains. You have an awesome "vision" on how to do those things. Others have a different view on things, and that is OK, Just state your different sets of advice and Do not get in a "MY way is better" argument. Some like to do it one way and some like to do it another. We have all levels of skills on this forum and all levels of "financial" levels.
I know that most everyone on this forum appreciates the advice that they get from ALL of the knowledgeable folks.

Let us all help this Young man out and help him "learn". He may just be one of US in the future, helping others "fix" their vehicle, when we are long gone, and the knowledge that we all have is gone. Appreciate and value all the members here. Oh, and If anyone has an issue with what I have put, respond to my personal email: lbesq@cableone.net. Always willing to talk.

Lloyd Bledsoe

Another thing that can make the difference is location, Where MM lives and works, what is available can be very different than what is available in midwest farm country. Here there are a lot of farmer still using Farmall H's and the like. There are at least three stores in town here that stock 6 volts in group 1, 2, 4 and 3EH. Prices are the same for "commercial" batteries" regardless of voltage. There are other stores that I don't frequent that also may stock them, I don't know. I imagine the same holds true in rural Indiana. We still have farmers moving grain in gas engine trucks with 5+2's and tag axles, much as it was in the 40's, but more 366's, 361's and 392's than 269's but that is the only major change.
I'm just suggesting as he already has a battery, generator and such to "run what he brung" as the saying goes. If at a later date he wants to update then we can address that.
with Soild State voltage convertors, my prime objection to 12 volt conversion has been addressed, You can keep your stock gauges and even blower fan, and still have 12 volt if that's what you want.

Nobody move.
https://youtu.be/kaJ97azaTdk

My dinosaur wrestling days are over. You guys can stay in "1962 land". I'll move on with the calendar if that's OK. I hear that GM is coming out with a transistorized ignition! Quite the deal! And that tires are going tubeless... Self-shifting transmissions are just around the corner!
Don't let ANYTHING push you guys into the next millenium!
Why in the world did I waste any time here?
C'ya!