How To Tell Rear-End Ratio

Ever wonder how to tell what gear ratio is actually in a Pontiac rear pumpkin, and if it is a Posi-Traction?

Check the end of the axle, or the pumpkin, for a paint daub. 

Paint daubs on the pumpkin and on the rear axle flanges. If posi, it will have a green daub in addition to a color daub that identifies the ratio. The green daub on the pumpkin is usually near the oil fill hole, and the color daub is more up on the snout near the pinion yoke.

These are the paint codes:

Gray - 2.56
Red - 2.69
Orange - 2.87
Yellow - 3.08
Brown - 3.23
White - 3.42
Blue - 3.64
None - 3.90

Green, in addition to an above, is Posi.  No Green, it's open.

The yellow daub in the center below signifies a 3.08 open rear end.  Pretty easy.