fatbuick Posted February 9, 2020 Share Posted February 9, 2020 Hi Guys, Just wondering if anyone has a 65 Riviera PosiTraction Diff they want to sell. I think they came out in 3.07 and 3.23 ratios so I'll need to know that. PM me if you like Thanks Link to comment Share on other sites More sharing options...
1965rivgs Posted February 9, 2020 Share Posted February 9, 2020 Hi Tony, As I`m sure you know the positraction option can be found with a 3:42 gear or could be combined with any ratio when new...unless I`m unaware of some exception. I currently own a `66 full size Buick equipped with a 2:78 posi as per the build sheet. Best to decide what ratio you ultimately want as that may affect which posi carrier you need. The carrier for a 3:42 gear is different as compared to the carrier for a 3:23 gear...unless you want to get into spacers, etc.. Tom Mooney 1 Link to comment Share on other sites More sharing options...
fatbuick Posted February 9, 2020 Author Share Posted February 9, 2020 Thanks Tom, I wasn't aware of that. I'll work out what ratio I need. From what years can I fit a 65 Riv diff housing? For example would you 66 2.78 center fit in my housing? Link to comment Share on other sites More sharing options...
1965rivgs Posted February 9, 2020 Share Posted February 9, 2020 27 minutes ago, fatbuick said: Thanks Tom, I wasn't aware of that. I'll work out what ratio I need. From what years can I fit a 65 Riv diff housing? For example would you 66 2.78 center fit in my housing? NO...Buick changed to a different type of diff which is not a drop out center starting in `66. I`m positive the `63-`65 diff centers will interchange and possibly earlier. I have seen conflicting info regarding number of axle splines for earlier side gears which would be a disqualifying factor but if I had to venture a guess I would think a `62 diff center section would also work, BUT THAT IS A GUESS. Tom 1 Link to comment Share on other sites More sharing options...
telriv Posted February 10, 2020 Share Posted February 10, 2020 The side gears on a '62 are 31 spline as opposed to the '65 Riv. which is 30 splines. So in Tony's case it would be '63-'65 Full Size & Rivs. I have a brand new never used '65 Posi Carrier for 3.42 & up gears all the way to 4.45 gears. Link to comment Share on other sites More sharing options...
RivNut Posted February 10, 2020 Share Posted February 10, 2020 54 minutes ago, telriv said: The side gears on a '62 are 31 spline as opposed to the '65 Riv. which is 30 splines. So in Tony's case it would be '63-'65 Full Size & Rivs. I have a brand new never used '65 Posi Carrier for 3.42 & up gears all the way to 4.45 gears. So I could transplant my 3.91 ring and pinion into your carrier, and use the housing and axles that are currently in my 64 with its 3.07? Link to comment Share on other sites More sharing options...
telriv Posted February 10, 2020 Share Posted February 10, 2020 Possibly ED as I bought it for my '64 then fond out by using the 4.45 gears I wouldn't make it to the end of the 1/4 mile before the engine ran out of RPM's. It was over $300.00 with my shop discount. I think retail it was around $400.00 + dollars. Over the years I have found out it was for a '65, but that it should fit in my car. I talked to Tom Mooney about it & he told me that it's a one year or so only & VERY RARE especially being NOS. Link to comment Share on other sites More sharing options...
1965rivgs Posted February 10, 2020 Share Posted February 10, 2020 3 hours ago, telriv said: Possibly ED as I bought it for my '64 then fond out by using the 4.45 gears I wouldn't make it to the end of the 1/4 mile before the engine ran out of RPM's. It was over $300.00 with my shop discount. I think retail it was around $400.00 + dollars. Over the years I have found out it was for a '65, but that it should fit in my car. I talked to Tom Mooney about it & he told me that it's a one year or so only & VERY RARE especially being NOS. Hi Tom, I remember you and I speaking about the case but I dont remember why I suggested it was a one year only case? I would think the case would work on `63-`65 diffs as we know they are interchangable. It is rare to see an NOS diff case to come on the market. Having said that, as you well know and better than most of us, there are many more parts to the posi diff besides the case. I have most of those parts that I have collected over the years and would be interested in buying your case. I`d like to build a 3:91 diff to have on hand in case I have the opportunity, in my retirement, to do some drag racing ! Please send me a message with details if the diff case is available, thanks, Tom M Link to comment Share on other sites More sharing options...
fatbuick Posted August 5, 2020 Author Share Posted August 5, 2020 Hi guys, let’s say I find a 3.42 posi from a 65 Riv and I have a 3.07 open diff can or use the posi parts from the 3.42 with my parts to make a 3.07 posi? You can see I don’t have a deep knowledge of the correct terminology but happy to rely on your knowledge 🙏 Link to comment Share on other sites More sharing options...
psychostang Posted August 19, 2020 Share Posted August 19, 2020 Fatbuick: Unfortunately, the 3.07 and 3.23 ring gears are too small to fit on the 3.42 carrier unit. Link to comment Share on other sites More sharing options...
BulldogDriver Posted August 19, 2020 Share Posted August 19, 2020 Saw this the other day. Good luck Tony. http://www.v8buick.com/index.php?threads/59-to-65-big-buick-3-42-posi-pig-36-xxx-mile-unit-from-a-totaled-65-riviera-gs.360431/ Ray Link to comment Share on other sites More sharing options...
fatbuick Posted August 20, 2020 Author Share Posted August 20, 2020 Thanks for your input guys. I've learned a bit recently and what you say is correct Andrew as confirmed by Jim at JD Race and said this and kindly attached the picture: "3.07 and 3.42 take a different carrier. The offset height is different like in this picture. " Link to comment Share on other sites More sharing options...
1965rivgs Posted August 20, 2020 Share Posted August 20, 2020 1 hour ago, fatbuick said: Thanks for your input guys. I've learned a bit recently and what you say is correct Andrew as confirmed by Jim at JD Race and said this and kindly attached the picture: "3.07 and 3.42 take a different carrier. The offset height is different like in this picture. " Did you read the first response in this thread? Not sure if the poster knows what he`s talking about but he said: " Best to decide what ratio you ultimately want as that may affect which posi carrier you need. The carrier for a 3:42 gear is different as compared to the carrier for a 3:23 gear...unless you want to get into spacers, etc.. Tom Mooney " 🙄 Mr. Newbie Link to comment Share on other sites More sharing options...
fatbuick Posted August 20, 2020 Author Share Posted August 20, 2020 Hi Tom, Of course you are right. I did read it but being dumb I didn't know what it all meant. Now I think I do Link to comment Share on other sites More sharing options...
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