story identification - Looking for a book series from the 1960's - NOT the Tripod series

I'm looking for a book series from the mid-1960's. I only ever got to read the first book as (apparently) the others hadn't come out yet - this would have been in the 1965-66 time range. If I recall correctly it vaguely resembled the Tripod series, but was set in the eastern United States. One plot element I remember clearly was that the parents of the protagonist were worried that the protagonist's younger sister was unusually small and might be declared to be "a dwarf", although I don't recall why that was such a terrible thing. Any pointers appreciated.

EDIT

Sorry - poor explanation on my part. If I recall correctly it's set in a post-apocalyptic future world - it may have been a nuclear holocaust, or it may have been aliens-coming-down-from-the-skies - where technology has regressed to the late-middle-ages level - lots of mud, not much in the way of "modern" conveniences like electricity and running water. I recall that there's a "religion", and that one of the protagonists friends is chosen to be trained as a "priest" of this religion. Before being "chosen" he was very religious, but afterwards he (apparently) learned it was all a sham and would answer questions about it by hanging his head and saying something like, "Yes, the gods are real...". The protagonist, BTW, was male.

Answer

It sounds like you are thinking of the Sword of the Spirits trilogy, by Tripods author John Christopher. Many details fit: It is post-apocalyptic; people who are born too short are considered dwarfs (and consigned to jobs like blacksmithing); the protagonist spends time as an acolyte of fake spirits/gods in which he previously believed; and obviously it is stylistically similar to the Tripods books.

The three books are The Prince in Waiting, Beyond the Burning Lands, and The Sword of the Spirits. They were published from 1970 to 1972, which is a little later than you thought, but not too far off. The most notably difference from what you describe is that the books are set entirely in the British Isles. The hero, Luke, is from Winchester; the high priests of the spirit religion live under a ring of standing stones near Salisbury (Stonehenge, although not named in the story); and the plots of the second and third books involve commerce with Wales, which has been mostly cut off by a range of active volcanoes.