Guest clamshells Posted July 1, 2014 Share Posted July 1, 2014 Came across this and had to share. http://www.ebay.com/itm/1965-Buick-Posi-rear-3-91-Riviera-Wildcat-1964-1963-Rare-as-hens-teeth-/131229055887?pt=Vintage_Car_Truck_Parts_Accessories&hash=item1e8ddc7b8f&vxp=mtr Link to comment Share on other sites More sharing options...
RivNut Posted July 1, 2014 Share Posted July 1, 2014 Holy Cow Batman. Makes me wonder what my 3.91 open might be worth.Ed Link to comment Share on other sites More sharing options...
Guest clamshells Posted July 2, 2014 Share Posted July 2, 2014 Holy Cow Batman. Makes me wonder what my 3.91 open might be worth.Ed3:91 + nailhead torque must really launch when it hooks up..................Wow! Link to comment Share on other sites More sharing options...
alini Posted July 2, 2014 Share Posted July 2, 2014 Holy Cow Batman. Makes me wonder what my 3.91 open might be worth.EdIt will be worth what someone is willing to pay Link to comment Share on other sites More sharing options...
JanZverina Posted July 2, 2014 Share Posted July 2, 2014 Damn - I KNEW I should've saved those hen's teeth! Link to comment Share on other sites More sharing options...
RivNut Posted July 2, 2014 Share Posted July 2, 2014 3:91 + nailhead torque must really launch when it hooks up..................Wow!It was in my '63 when I purchased it. The PO had it installed to raise the engine RPM's when he was towing his Airstream. Before that, he had burned a couple of valves by lugging the engine.I've since but a 3.23 in it. The car was my daily driver and I never really tried launching it with the 3.91 gears behind a Dynaflow.I have the all the parts and think about putting it in my '64 behind a 200-4R transmission. That would give me the advantage of the 3.91 rear for "launching" then with the 200-4R's .67 overdrive, I'd have a 2.62 highway gear. Can I burn this candle at both ends?Ed Link to comment Share on other sites More sharing options...
Guest carlbraun Posted July 2, 2014 Share Posted July 2, 2014 a 3.91 rear end should be good for about 3000 rpm at 60 mph... Link to comment Share on other sites More sharing options...
riv1964 Posted July 2, 2014 Share Posted July 2, 2014 Been running 3.9 posi gears for a few years in my 64 Riv, great around town. The 64 posi center section is different from the 65. I currently have the 64 TH Trans, a 200-4R built to hold up to the torque and weight of a Riv would be great..Roger Link to comment Share on other sites More sharing options...
Guest clamshells Posted July 2, 2014 Share Posted July 2, 2014 a 3.91 rear end should be good for about 3000 rpm at 60 mph...Stop light to stop light a Riviera out hurting guys tender little feelings.My 66GS had a 3:07 open installed due to the PO's owners wife was deathly afraid of the 3:42 locking, the 3:07 would break loose quite often. I found a 3:42 in a wrecking yard, not only was the speedo correct once again that 3:42 would jump pretty good, I can only imagine a 3:91. Link to comment Share on other sites More sharing options...
devildog93 Posted July 2, 2014 Share Posted July 2, 2014 Ed that combo sounds perfect to me. Hot in the city, comfortable on the highway. Getting back to the original post, that guy seems really proud of his rear end. Link to comment Share on other sites More sharing options...
Guest clamshells Posted July 2, 2014 Share Posted July 2, 2014 It was in my '63 when I purchased it. The PO had it installed to raise the engine RPM's when he was towing his Airstream. Before that, he had burned a couple of valves by lugging the engine.I've since but a 3.23 in it. The car was my daily driver and I never really tried launching it with the 3.91 gears behind a Dynaflow.I have the all the parts and think about putting it in my '64 behind a 200-4R transmission. That would give me the advantage of the 3.91 rear for "launching" then with the 200-4R's .67 overdrive, I'd have a 2.62 highway gear. Can I burn this candle at both ends?EdPopular set up for a lighter car, not sure about a Rivi, but sure sounds nice. Link to comment Share on other sites More sharing options...
Ted "Wildcat65" Nagel Posted July 7, 2014 Share Posted July 7, 2014 I was watching that auction to see if they sold. I'm sitting on 2 3.91 posi rears - have not tried them out ... yet. They are heavy - the Mopar guy that looked at it thought it was a Dana unit.Very different from the 65 Riv and Wildcat 3.42 posi units from the Automatics. All the 4-speed cars seem to have the heavy unit. Link to comment Share on other sites More sharing options...
1965rivgs Posted July 7, 2014 Share Posted July 7, 2014 I was watching that auction to see if they sold. I'm sitting on 2 3.91 posi rears - have not tried them out ... yet. They are heavy - the Mopar guy that looked at it thought it was a Dana unit.Very different from the 65 Riv and Wildcat 3.42 posi units from the Automatics. All the 4-speed cars seem to have the heavy unit.Ted, I`ve come across both types in automatic cars. Probably just a matter of what was on hand at the time of build. Tom Link to comment Share on other sites More sharing options...
Guest clamshells Posted July 7, 2014 Share Posted July 7, 2014 So much for a 3:91 posi "rare as hens teeth" and for 1200.00 you still need a housing (no big deal on the housing) but need the axles too. Just my 0.02 a 3:91 posi w/o axles showing no excessive wear going for 750.00 would be fair to both seller and buyer. Link to comment Share on other sites More sharing options...
RivNut Posted July 7, 2014 Share Posted July 7, 2014 My car came equipped with the stock 3.07 rear, then the PO put the 3.91 in it. I took the 3.91 out and installed a 3.23; the only thing I could find at the time. Each of these swaps was done with the same axles. I seriously doubt if Buick changed the number of splines on the axles for different rear end ratios. Link to comment Share on other sites More sharing options...
1965rivgs Posted July 9, 2014 Share Posted July 9, 2014 So much for a 3:91 posi "rare as hens teeth" and for 1200.00 you still need a housing (no big deal on the housing) but need the axles too. Just my 0.02 a 3:91 posi w/o axles showing no excessive wear going for 750.00 would be fair to both seller and buyer.Mike, The 3:91 gears are very unusual, Ted is an aggressive collector. Also, the carrier is a big deal because the performance gears (over 3:31) have a different carrier because of the thickness of the ring gear. In other words one cant use a 3:07 posi carrier and install a set of 3:91 gears. A spacer can be used but... Tom Link to comment Share on other sites More sharing options...
MartyWorld Posted May 4, 2018 Share Posted May 4, 2018 On 7/7/2014 at 5:14 AM, Ted "Wildcat65" Nagel said: I was watching that auction to see if they sold. I'm sitting on 2 3.91 posi rears - have not tried them out ... yet. They are heavy - the Mopar guy that looked at it thought it was a Dana unit. Very different from the 65 Riv and Wildcat 3.42 posi units from the Automatics. All the 4-speed cars seem to have the heavy unit. Good afternoon. Did you ever sell the 3.91's? Thank you, Marty Link to comment Share on other sites More sharing options...
Ted "Wildcat65" Nagel Posted May 4, 2018 Share Posted May 4, 2018 No plan to do that, still in my aggressive collector hands. 43:11 ! 2 1 Link to comment Share on other sites More sharing options...
1965rivgs Posted May 4, 2018 Share Posted May 4, 2018 Lol...Ted, I think it already is, but just to be clear, my description of you as an aggressive collector was intended to be complimentary. Quite honestly, I`ve never witnessed a collector visibly shake when there is mention of a 4 speed big car.....you know it`s true! Maybe someday I will graduate to "aggressive" status?! Tom PS I miss the slammin gears emoji ! 1 Link to comment Share on other sites More sharing options...
telriv Posted May 5, 2018 Share Posted May 5, 2018 Not only do I have 3.90's I also have a set of 4.45's. With the 3.90's launch is hard WITHOUT slicks. Good enough to pull the front L wheel. Would be GREAT with a 200R4. The 4.45's would be even better with a 200. Best time I have run so far is a 13.902@98MPH. Not too bad for 4400pds. & over 200K on the original engine. 1 Link to comment Share on other sites More sharing options...
Chimera Posted May 6, 2018 Share Posted May 6, 2018 1 hour ago, telriv said: Not only do I have 3.90's I also have a set of 4.45's. With the 3.90's launch is hard WITHOUT slicks. Good enough to pull the front L wheel. Would be GREAT with a 200R4. The 4.45's would be even better with a 200. Best time I have run so far is a 13.902@98MPH. Not too bad for 4400pds. & over 200K on the original engine. Got any footage? Link to comment Share on other sites More sharing options...
Ted "Wildcat65" Nagel Posted May 6, 2018 Share Posted May 6, 2018 On 5/4/2018 at 5:24 PM, 1965rivgs said: Lol...Ted, I think it already is, but just to be clear, my description of you as an aggressive collector was intended to be complimentary. Quite honestly, I`ve never witnessed a collector visibly shake when there is mention of a 4 speed big car.....you know it`s true! Maybe someday I will graduate to "aggressive" status?! Tom PS I miss the slammin gears emoji ! It is a perfect description, I had to laugh when I saw it...so true especially wen it comes to the 3 pedal Wildcats. Link to comment Share on other sites More sharing options...
telriv Posted May 6, 2018 Share Posted May 6, 2018 Ted, I'm sure you are in LOVE with Matt's '64 Cat Conv which he made a Super Wildcat Link to comment Share on other sites More sharing options...
Seafoam65 Posted May 7, 2018 Share Posted May 7, 2018 (edited) I was visiting a farmer friend over the weekend to buy a complete Riviera rear end with 3.91's in it that was sitting in his barn since 1967. While I was there I bought one of his roosters to add to the flock in my hen house.................. Edited May 7, 2018 by Seafoam65 (see edit history) 1 Link to comment Share on other sites More sharing options...
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