try going to HERE it is a list of a lot of junkyards through the country, that is where I found mine for my Electra.
I have a complete 3.07 posi rear from a '67 I could sell you that will bolt in but the shipping would be a killer. :bglasses:
ok well I will look into around how much shipping would be is that the same posi that the riviera came with in 66?
The standard Riv came with 3.07 one wheel peel. As an option, 3.07 POSI was available, and I would presume 3.23, 3.42, and 3.91 were also in the offing. On the Riv GS, 3.42 was standard with the GS option. :bglasses: