I was taught that the Latin c was pronounced "k", and that v was pronounced "w" (English "w"), the sounds "ch" and "v" (hard) being confined to "church" Latin.
"v" and "u" seem to be used interchangeably in inscriptions, but "u" would still suggest a sound like Welsh "w". Perhaps the Romans had problems with how foreigners spoke their language too!

Like written music, the written form of a language is only an approximation (except to the Victorians for whom everything had to be "correct"), and the spoken or played form (which is the real thing) can vary considerably.