The metal Schrader-type valve stem on the replacement inner-tube I'm using is of a smaller diameter than the valve-stem hole in my felloe—the previous inner-tube having had a wider, snug-fitting valve stem. -Does that matter? -Do I need some kind of adapter or is that not really necessary?
I don't feel that it would be a problem. When you screw down the dust cover the hole and gap will be covered.
Others may offer an opposing opinion. Good luck with your project, Bill
The large diameter stems are what the repop tubes are using, and are not correct. The smaller size is what Ford used. There have been plenty of articles posted on this subject.
https://www.google.com/search?q=correct+valve+stem+mtfca&rlz=1C1CHBD_enUS737US73 7&oq=correct+valve+stem+mtfca&aqs=chrome..69i57.5743j0j7&sourceid=chrome&ie=UTF- 8