q's about my rear end

... no not that rear end the one in my 71. Its an 8.5 as far as i could identify. it has the 2 metal ears on the bottom of the housing. Also i went out and did a burnout and guess what... POSI. i dont know if its factory or not or the gear ratio. any help would be great.

There should be a code on the pass side tube on the front side that will tell you what it was originally,also if you jack it up and mark the top of the tire and spin it one full revolution while counting the pinion U-joint rotations it will tell you the gear ratio that's in it now.:D Do you have a pic of the ears?They are usually on the top if it is a Chevelle rear.

no there on the bottom.

To the best of my knowledge, the 8.5" didn't come factory until '72...so it's probably been swapped out in the past...not too suprised to be honest!

As for the "burnout test" my old open carrier would leave 2 black strips from time to time...but usually not. Another way to check would be leave one wheel on the ground and jack up the other side. Try and spin the tire...if it won't spin (and the brakes off/neutral) then you're posi.

yeah but a loose clutch type limited slip will spin with the tire off the ground too. it always leaves 2 marks on a burn out to. i think my tires are 255/60r15 with lakewood traction bars.

This site will help you figure out what rear end is in your car. You may have to get the codes off the rear axle housing.

http://novaresource.org/axle.htm

The latter half of 1971 the 8.5 started to appear .

Dont forget that the 1972 nova debuted in September 1971

the 8.5 did not start with the 72 it was standard on the 72, it was introduced in the last of the 71's

so you may very well have a factory installed 8.5