Marcel,
I have been down this road over the past years with my carrier and there was a thread on here all about the water pumps though I can't find it now. I have now tried both the single pulley modern pumps and rebuilding the originals, have had the pumps off and on 4 times so for what it is worth here are my findings. The Jeep pump bearings are the same size but the shafts are not so would need grinding down to fit the Carrier pulleys/impellor. I have fitted the modern single pulley pumps which are excellent and water tight if you are happy to run a single pulley which is of course not original, it does depend on how original you want the engine bay to look, if you are not too worried I would go that route for both cost and peace of mind. I have also had my original pumps rebuilt 3 times now, twice by a cowboy outfit who used Chinese bearings which lasted a few minutes running and lastly by a decent engineer using new rebuild kits from the USA. These have done well so far though I have just had a small leak from one probably due to not having run the Carrier for the past year. I bought the pump kits from Gotham Autoparts in New York
sales@gothamautoparts.com You want the 1937-1948 Truck Dual-Belt Water Pump kit Looking at the invoice I think the part number is 79-8591. When rebuilding the pumps you need to find an engineer with the ability to reface the inside of the pump body casting against which the carbon disc sits, if this is scored the pump will never be water tight.
Hope this helps.