[quote=oldskool]"...The 8.5" 10 bolt didn't come out until 72..." Not trying to start an argument. But it is commonly known that lots of vehicles came with an 8.5 rear end in 1971. I've read that most all '71-'81 F-body cars had an 8.5. Can easily be confirmed with an online search.
I am not either, . I was referring to the X- Body cars as they are the ones that will bolt into the 1st gen F-Bodys with no mods, other than the driveshaft. But I was not aware of the 71 F-Bodys having the 8.5"