If memory serves 3.23:1 . This is what my 65 Riv has as well. A 65 GS Riv would have a 3.42 posi. 3.08: 1 was an option, and 3.91:1 was also and option. I'll try to dig up the document (chassis manual or sales manual) to make sure.
I think the big Buicks with the 400 trans generally had the 3.07 gears and dynaflow (earlier) usually had the 3.23 sets. Saying that we parted a '65 Riv and few years ago with A/C that did have 3.23-
my 64 riv has a 3;08..... wire brush the bottom of the case right under the ''ham''..... there will be symbols and numbers stamped onthe case.... the numbers will be 08 for a 3.08 ratio 42 for a 3.42 23 for a 3.23 ect..... a circle with an x in the middle of it denotes a posi.....
My '64 Riviera has a 3.23 Posi, my old '65 Riviera Gran Sport had a 3.42 Posi. I think its an orderable item but the base ratio seems to be the 3.08 for most of Buick's full sized cars but the Riviera being more sporting might have had a shorter rear axle ratio.
Standard gear for a `65 Rivi is 3:07. Dynaflow equipped earlier first gen are 3:23 as Dan stated. However, any of the ratios referenced can be found frequently with the 3:42 only in GS models. I have never seen a 3:42 in a straight Riv. Tom Mooney
The "Features and Facts" book lists the 3.23 as standard, and the 1965 "What you should know about the 1965 Buick" book has it listed as 3.23...then in the same paragraph there is a misprint that says "1964 Riviera"...1965 chassis manual list standard as 3.07:1. I think Tom is right, they probably had the '64 info and just missed the editing! :beers2:
My post was based on the cars I`ve dis-embowled over the years. I really should have also checked the factory literature before I posted. I reviewed the `65 Facts and Features booklet and as near as I can tell (it`s late and the evening before St. Paddy`s Day) the booklet indicates the standard gear for a 401 equipped Riv is 3:23 and for a 425 equipped Riv the standard gear is a 3:07. It seems odds are I would have encountered more Rivs with the standard 401....but time flies and memories fade. Perhaps the 401 cars have 3:23`s but I missed it??? o No: I must confess it always felt like the 401 equipped cars had a little more "seat of the pants" when uncorked. I always assumed it was a more aggresive cam in the 401 until I saw the specs....maybe it was the gear??ou: I think a survey is in order!! :Smarty: Tom Mooney
thanks for all the info guys. My dad is kind of spearheading this project so ill pass the info to him. He said its a posi for sure but i dont think he has determined what the ratio is yet.
