Am guessing you do not have a posi (to confirm you do NOT have one, jack up both rear tires off the ground, turn one one way, if the other turns the other way, you do not have a posi. If non-posi, and it was just over 2 revs of driveshaft, then probably a 4.11, if just under 2 revs of driveshaft, then probably a 3.73 - but here's the procedure:
from
http://www.how-to-build-hotrods.com/gear-ratio.html
Posi: Jack both wheels off the ground. Turn one wheel 1 complete turn.
- Count the turns on the drive shaft.
Non-posi: Jack one wheel off the ground. Turn the wheel 2 complete turns.
- Count the turns on the drive shaft.
If it takes about 2 and three-quarters turns, it's around a 2.73 gear ratio. If it's a little more than 3, you have 3.08s. If it takes about 3 and a quarter turns of the driveshaft, you have 3.23 or 3.25 gears. Very close to 3 and three-quarter turns, 3.70 or 3.73 gears. This method won't work very well on a posi that's worn-out and won't spin both tires equally.