I have a 1966 Chevy Impala 4 DR. Sedan with a 406 SBC and a TH350 in it, that I'm trying to findout any information on the stock rearend? I know it is a 10 bolt, but any other information would be greatly appreciated. I want to put a POSI in it but don't know if it has a 8.2 or a 8.5? 28 Spline axles or 30 Spline?

Thanks for any help in advance!!

I post this again by mistake!!

The 8.5 was not used until 1970, You should have a 28 spline 8.2. The Eaton posi part# is 19603-1 and that unit is for 308 & lower gear ratio's.

Thanks for the reply Prostreet

Thanks again Prostreet.. So I could actually look for a 8.5. or a 8.2 posi unit?

You need one for a 8.2! the 8.5 and 8.2 are different.