I have found a 8.2 10 bolt posi axel out of a 69 chevell. Will that fit into my 71 cutlass conv? I am not sure what I have now I just know it's not posi.

 

If you swap the complete rear end yes it will fit. The Chevelle yoke is a different sized U-joint, but you can purchase a U-joint that has 2 caps for the Cheby yoke and 2 caps for the Olds driveline. I believe that would be the simplest way to make it work. John