thanks scoutpilot. That is good to know. I have read that some CJ3B's (F-heads) had YF964S's installed at assembly in-plant. But perhaps that is not correct.
I will look at acquiring a YF938 (rebuilt, or one to rebuild), or perhaps the "Universal" replacement carb that both Jeepsterman and Kaiser-Willys sell.
Any thoughts on that Universal carb? Here's the link to it on K-W:
https://www.kaiserwillys.com/new-fully-universal-carburetor-fits-50-71-willys-jeep-with-4-134-f-engine