For a non-posi rear end, if you jack up one wheel only and turn it one revolution, the number of driveshaft turns will be half of the ratio.
What you may have counted was the number of times the u-joint bearing came into view, which makes your rear end a 3.08.
Jim was right, but he just guessed lucky. Fuzzy math works mysterious ways.
To get the right answer, jack up the one wheel and spin it TWICE while counting the number of turns of the driveshaft. Mark the companion flange and the housing with white-out to make this easier.
