I have an A-body 8 1/4 rear that I am ready to install the suregrip and 3.55 gears I have. I am looking at the install kits from Randy's and they list 70-75 and 76 and up. Its from an A-body so the chances of it being the 76 up are slim but I want to make sure.

I am not finding any date codes on it so how do tell? Thanks