*lost*, I'll go for the w rather than the v. Here's a few sources that point to waw, pronounced as w.
Waw (or wâw) : This is the sixth letter of the Hebrew alphabet, being in the shape of a hook. In the Phoenician alphabet, the angle of the hook is even more acute. Waw is frequently used as a vocalic consonant (semi-vocalic consonant: w = û, ü or ou). It corresponds closely with the English w (- double u -) rather than the v (uâu, u = w; e.g., in was, wine; Driver SW 155.178f). This applies to yahwêh, the latter having been vocalized as yahua with an audible h. In compound names it was changed to –yâhû, the final a losing its emphasis, disappearing, and ua becoming û. In early Hebrew waw was pronounced as w. In late Hebrew a w that began a word or syllable changed to y (as in the pe-waw verbs and the verb hayâ itself). See written form yehyâh (=yehwâh) of the first century (cf. yeyâ of the Tiberian Targums) as well as pronunciation yâhyâh (cf. Ia.Ia of Isidore from the 7 th century). [i]
Edward Horowitz confirms that the sound of the letter waw is not v but w, and that waw is the sixth letter of the Greek alphabet (as in Hebrew), later becoming extinct. Jews of Yemen, Arabia, preserving the most pure, accurate, and ancient pronunciation of the Hebrew language, pronounced it as the English w (e.g., was, wine) as in Arabian, a close relative of Hebrew. [ii]
N.B. Pronunciation of above letters would differ in the early consonantal text and the later, vocalized MT. Vowel letters would play an important role in the pronunciation of the CT (up to 200 CE). After full Masoretic vocalization had taken place (from ca. 700 - 1100 CE) the vowel letters would lose their significance.
[i] F. Dietrich, in a letter to F. Delitzsch. See ZAW 1883-4, pp. 2 80, 293, 298.
[ii] E . Horowitz, How the Hebrew Language Grew, 1960 edition, pp. 29, 30.