[Rev]

Originally posted by mustangII460
Mark a axle and turn the pinion. See how many turns the pinion takes to complete one revolution of the axle. It will get you close.


Number of Turns Approximate Gear Ratio
2 - 3/4 2.72:1 or 2.77:1
3 - 0 3.07:1
3 - 1/2 3.54:1
3 - 3/4 3.73:1
4 - 0 4.10:1
4 - 1/2 4.56:1
4 - 3/4 4.88:1

That's right as long as both rear wheels are turning as in a limited slip or spool with both wheels off the ground. If only one wheel is off the ground and rotating, as in an open rear axle, then the wheel will make twice as many revolutions for the same number of pinion turns. You then need to count the number of pinion turns for 2 wheel revolutions and just use Franks chart. I agree that Currie 9" center sections are almost always going to be limited slip of some persuasion so what Frank says is certainly correct. I did have to do the two revolution thing when checking an open axle once though.

Rev