Are there words in English with the letter C in which it's really pronounced as Z?
By googling I found an old book which counts these words as in which letter C sounds like Z: suffice, discern, sacrifice. But checking it in Cambridge dictionary raises that it is not true or not updated and those words pronounce as C rather than Z.
Another old book (The Oxford Spelling Book) says:
"C sounds like Z in squinancy which is pronounced like quinzy"