Ok its my understanding that all 73-91 GM trucks will interchange the rear axles, 10 blt, 12blt and 14sf&ff. W/ the exception of the 1 tons. I was calling around my area looking for a rear 10 blt for flblazer's blazer, and the guy at the counter ( who I know is knowledgeable having known him for several yrs ) argued that there is differences in the yrs of blazer and the truck wont interchange (as far as 10 blts go, thats all we dicussed) I was correct wasnt I?? I hope I was. Out of 100,000 sperm, YOU were the fastest??