I was impressed to read the Oxford English Dictionary attribute the phrase Shut you pie hole,’ to Stephen King. The OED says, ‘The earliest known use of the noun pie hole is from 1983, in the writing of Stephen King, novelist,’ in his novel Christine. Looking into this subject further, however, (going down the pie hole, as it were) I learned that a character in Sally Field’s 1979 movie Norma Rae, written by Irving Ravetch and Harriet Frank, tells her, ‘Norma, shut your cake hole!’ So I’m less impressed with Stephen King and the OED. They should shut their pie hole.
I have a friend who’s employed since the 1980s by the OED in the U.S. as a word-origin sleuth/editor. He spends most of his time in the Library of Congress. This in fact may be his entry. I’d ask him, but I’m afraid he’ll tell me to shut my pie hole.