I don't think there is much of anything that makes it change once set.

About the only thing that can change is the length of the tiny spring inside the needle.....or the rubber tip can get worn and should be replaced.

Are you sure the float floats ? Old floats , brass develops tiny pinholes and plastic tiny cracks.
Only use gasoline for testing , fill a container deep enough to completely cover float, weight the float with just enough weight to keep it submerged, add extra gas to allow for evaporation and leave it , check it in 24 hours.
When restoring old carbs I will always replace the float if available .
I prefer the solid plastic floats they always float.
Jog make sure float bowl vent is clear and operational.

Plugged pilot circuit , how long since it ran before problem ?
I've had many ford six cylinder and rebuilt many carbs , they are as simple as it gets. You may need a carb kit (cheap) & new filter !
Don't be skeered , take it apart , blow it out , make sure you can see thru the jets , put it back together , take pics on disassembly & review on assembly , super easy , you can do it ! What size is engine ?

Git a kit , sometimes you can flat file that warped housing. Good Luck