I believe if you jack up the rear end and turn one wheel by hand, the opposite wheel will turn the same direction if posi. If open rear the wheels turn opposit way.
No not all came with Posi rears,and if it's a factory Posi it will have a large P on the pumpkin face.Up until 64.
Not all SS cars came with a lot of things it was all on the option list. I once had a '64 Impala SS that I bought from the lady who bought it new. SS package, factory A/C, power steering and brakes, console, vacuum guage, and 230 6 with 3 on the column. Many SS 396 Chevelles in '66 to '72 did not have Posi.
-------------- Nope. The SS was was merely a trim package. 'Positraction' was available as an 'extra-cost' option on Chevys with the SS' package, the same as it was on any other, lesser model Chev of the same year. Mart3406 ==================