I have an '84 Z28 with an A4 transmission and what i believed to be a tall gear (2.73 or 3.08) peg leg rear. I was messing around in a parking lot after work and did a burnout on a section of pavement that was partially wet. Funny thing was, i lit both tires up even though the right tire was in water and the left was not. I figured that the wet right tire would go up in smoke while te left wouldn't move. Today, i tried to check for a posi and the gear ratio by jacking up the car and spinning the tires. This is what i found:
With the right tire up and the left on the ground, the driveshaft spun less than 2 times per rotation of the tire.
With both off the ground, the left didn't turn when the right was rotated forward, but went the opposite direction when the right was spun backwards. When it did this the driveshaft didn't spin at all.
I decoded the RPO and found a 3.23 open rear, but why didn't the driveshaft spin that many times? I plan on upgrading the rear (posi and gears) but i'd like to know what i am upgrading from.

DG

 

pull the cover and look, only 100% accurate way to know what you have and it'll give you a change to change the oil and posi additive if you have posi.