You talking about those little 90° push-on types?
They are sold at just about any auto parts store, but I've found they don't always fit very well either. Sometimes they're so tight they won't go on the stud. That may very well be because they weren't made for Ford stuff, but they "look" the same on the outside.
They're probably rated by stud size, but I'm not sure what sizes are offered.
I'm thinking Dorman/MotorMite, and a few other old-time suppliers, but not sure. I'd bet that at least some of them have dropped them from the lineup.
Most of the harness manufacturers simply use ring-terminals and nuts now.
What is wrong with your old ones? If they're just loose, in a pinch (no pun intended) you can squeeze them carefully with pliers to fit better. If they're rusty though, all bets are off.
Good luck.
Paul